T-38 Talon Park Jet

[jetset44]

Here are BETA plans for the latest member of the Park Jet series, the Northrup T-38 Talon. This design is very similar in concept to the F-18 (http://www.rcgroups.com/forums/showthread.php?t=271581) and F-15 Park Jets (http://www.rcgroups.com/forums/showthread.php?t=289276), and uses the same construction methods and recommended power setups. Like the other jets, it’s intended to be a true park flyer built with simple construction methods and using inexpensive and readily available components. Here are the specs:

Wing area: 218 sq in
Span: 28.2 in
Length: 45.4 in
Weight RTF: 15 – 18 oz
Wing loading: 10.9 oz/ft2
Motor: GWS EPS-350 with C gearing (or brushless equivalent)
Battery: 1200 – 1500 mAh 11.1V Lithium-polymer
Prop: 8x6 (EPS-350) or 9x6 (brushless)
Flight controls: Wing flaperons, full-flying horizontal stabilizer

The general wing planform and tail moments of this design are fairly similar to the F-18 Park Jet, so I’d expect the T-38 to fly similarly. However, because the real T-38 has such a small wing area this design also has a smaller wing area than the F-18 Park Jet (218 vs 254 sq in), making the wing loading a little bit higher. Thus, the T-38 will be a little hotter than the F-18, but if the weight is kept low it should still qualify as a park flyer.

The reason I’m posting beta plans is because these plans have been done for nearly a month and I haven’t had time to build it yet, and with the holidays approaching I won’t have the time to build it for at least another month. And since many fellow Ezoners have expressed strong interest in building this jet, I decided to go ahead and post the beta plans now and let you guys help work out the kinks! ;)

Please note that because these are beta plans they may have errors and that the CGs and control throws shown are untested. Thus, if you build this please take note of any errors or misalignments in the plans, and most importantly what CG and control deflections your finished model flies best with, and let me know. After I collect a list of improvements, I’ll update the plans (if I don't build my own copy sooner!). Both tiled and non-tiled files are posted below, as are previews of the plans.

Enjoy, and post pictures as you build this!

Steve

EDIT #1: (Aug 6, 2005) I finally had a chance to build this bird, so I've attached some photos below.

EDIT #2: (Aug 21, 2005). I updated the T-38 plans to fix several errors and include several design improvements, and also developed a new illustrated construction guide for this model. These are available in post #872 of this thread (link below):

http://www.rcgroups.com/forums/showpost.php?p=4195469&postcount=872

[Akura2]

That's AWESOME!... now you can get to work on this....

[Akura2]

or this....

[RoverTomcat]

Whoa - Steve! That'll be my next jet...

Thanks for publishing the plans! Now where did I put my sanding mask?

:)

Best regards - Paco

[Akura2]

BTW Steve... sorry to threadjack...lol


Great-looking plane!!!

[Ben_E]

Thanks again Steve!!!! :) :)

Do you know how many you are driving crazy these days....

I just had a look at he plans -a and it's great work as usual
Thanks,

Ben_E

[hummingbird111]

Hey Steve,, that's a rocking plane,,:D... i've been looking around for something a little different than the F-16,, kinda similar too,,wow!! that's a cool plane:p,, i didn't know what a T-38 was till now :eek:,,thanks !!

[cyberbipe]

Thanks Steve,
I have built the 2 previous jets and the fly awseome I will have to get bussy on this one next. This is such a great thing you do by giving us these plans.
Michael

[ravencsr]

Thanks for the plans Steve !

The missus is not too keen on you for giving me the eagle and hornet to play with.... said I was spending too much time on my planes and not enough time with her ! :confused:

Now she's seen these plans :eek: !! (still haven't let on to her about the gripen ;) )

Guess I better get my priorities right.............. now where did I put my cuttin knife ?????

[J Morgan]

I must say Steve, you are a credit to the E-Zone and unselfish individual.
Thanks for all your contributions. Without saying, your plans are great!

J

[Spinner]

Steve,

What John said, multiplied by hundreds for the masses!

Joe

[Spinner]

Steve,

What John said, multiplied by hundreds for the masses! :)
Many thanks from all of us.

Joe

[empeabee]

I just thaught I'd copy this from the F18 park thread

Steve's Beer Fund ;)
Paypal account address: jetset44@verizon.net

Mike

[RNAF]

Is it in EDF version too?
Guys like jetset make this forum so popular!
Even though I "might not" make this one, I appreciate your effort and persistance :)

Hats off for Jetset44!

Dave

[T_MECO]

Thanks Jet for the official release of this thread. I had a chance to get a head start on this project. This plane does handle similarly to the F-15. However, It requires speed! This is not going to float around like the F-18, 15 foam planes. I used a axi 2208/34 with 9x6 SF prop. Controlability became an issue at low speeds. This baby lives for speed. I have some c.g. and rebuilding issues to do prior to my next flight. Seeing how my first attemp went off with mixed results.

[T_MECO]

by the way here is what it looked like pre crash. I wonder when I'm going to learn not to paint before I maiden these birds :D
T-38 NASA (http://tmeco.rchomepage.com/T38/paint%20002.jpg)


I do have a minute of footage but I have not downloaded it yet.

[Ceeray]

Thanks for the plans Jetset!

Gonna try this one , first thougt to build Su-27 from Nelsons plans, but this is easier first.

One question for people here: Can anyone enlarge plans say 20% and then make tiled again? I would like to make bigger model because I have engine ready ;)

Have to make a new plane, had a midair collision today with Rane´s new Depron Su-47 Berkut :eek:

He was coming and I was making low pass and pulled up... crash in midair! I lost wing but Rane´s Berkut is ok. The spitfire fuselage made about 80m free flying arc and then crashed.. well I fixed it already but its not the same... :(


Also I have thought about making the wing from 2 x3mm deprons, adding strip of depron between to make it look like a wing. Or then making lower part of 6mm depron and adding another 3mm part over the wing and sand it.

But WTG with these depron planes!! Rane is making plans with CAD for that Berkut , it flies nice and has some really weird manouvers to offer (say pugatchew´s cobra..) but I leave rest to Rane, not gonna spoil his sport! :D

BTW how much you have to modify this to get it look like F-5?

[Ralph A. D'Amelio]

Steve, good show!

I like your construction techniques. I only have fff expect depron to be here later this week. Maybe I will do stock in fff and increase by120% for depron, which would be comparable to my T-38.

Again excellent work.

Ralph

[Ceeray]

Hey Ralph, would it be terrible job to enlarge those PDF files? Because I am not very good working with image files... :confused:

And better yet if they would be ready tomorrow....

;)

[Ralph A. D'Amelio]

Ceeray, I just going to use the copy machine set to 120% and larger paper. Don't now much about PDF either.

My current T-38 really moves with a typhoon 15 and at 32 "ws and wt of 27oz. Its a size I can see well.

I just know Steves will be a winner as well.

Ralph

[Ceeray]

Ralph, thats the engine I´m gonna install, Micro-15.

That little motor is a winner, just changed bearings after a mighty crash (read earlier post). Running it with 1800 PQ pack 12-16c, and CC25.

Hmm using copymachine.. you have to use larger paper in that case I think..

I´ll try to find a way to enlarge untiled picture first. The best way would be that Jetset would enlarge that to us because he seems to know what he is doing.

Then I´m gonna paint it with Aggressor sqd painting from top gun.. :D

I got some pics, but all 3-way paint schemes are appreciated!

[Ralph A. D'Amelio]

Yes, I really like that motor, I run it with apc 10x7 and 3s/tp2100 it even hauls my 30oz F-4 at good speed. Yes you will need to use larger paper to copy larer.

[Ben_E]

BTW how much you have to modify this to get it look like F-5?

I'm looking at this as well. I don't have the painting abilities but I would love to have one like this one from the Norwegian Airforce!!:

I don't have any quality 3wiews so I can't say for sure what the difference is but the the F5B is much closer to the T-38 than the F5A.

The nose is much longer on the F5A than on the F5B

Anyone that could fill in with some details??

Ben_E

Airliners.net does not like to be linked to any more... :confused:

[Spinner]

T_MECO,

Nice looking model! :) Sorry about the crash, keep us posted.

Joe

[Ralph A. D'Amelio]

Easy to make look like a F-5 here:

http://www.airwar.ru/other/draw/f5a.html

Ralph

[Ben_E]

Easy to make look like a F-5 here:

http://www.airwar.ru/other/draw/f5a.html

Ralph

Thanks Ralph!

The only "big" difference seems to be to change the canopy and also add a little to the wing roots - shouldn't be too difficult :)

Ben_E

[jetset44]

Everyone's welcome for the plans. Wow, they've been posted less than 12 hours and have been downloaded over 100 times already! Popular plane! I very much look forward to hearing everyone's experience with the design. I was leery of posting plans for an airplane I haven't even built yet, but given the circumstances I thought it was the best thing to do... :D

Ben E - Yes, the only major differences between the T-38 and F-5 are that the F-5 has a single place canopy, small wing root strakes, and wing tip missle rails and/or fuel tanks. It would be very easy to simply build a different canopy piece--in fact, the design is such that you could even build both a T-38 and F-5 canopy to try both! Tonight when I get home I'll take the drawing Ralph posted and draw a scale F-5 canopy and strake outline and post them here for those that want to convert. I also plan to convert this design to an F-20 in the near future--stay tuned!

Ceeray - I'll plot new 120% scaled PDFs tonight and post them for you. Easy to do.

T-MECO - Sorry to hear the first flight was less than successful. I knew the T-38 would be hotter than the F-18 due to the higher wing loading and lack of strakes, but I have high hopes it will still be a parkflyer. To tame the T-38 down a little, I have two suggestions for you:

1) Set the flaperons at 10 degrees for takeoff, and if you're flying in a small field leave the 10 degrees flap in the whole flight. This really helps slow down the F-18 Park Jet and I think it will work well here, too.

2) Enable elevator-to-flap mixing so that full up elevator input drops the flaperons about 15 degrees. This adds additional lift during turns and landing flare that helps compensate for the small wing.

Note that I intentionally raised the wing on the fuselage of this design relative to the real T-38. The reason for that was to provide some flap clearance for belly landings. If the wing were in the scale position near the bottom of the fuselage, you wouldn't be able to land with flaps since it would strip the servos... :eek: I also raised the horizontal tail a little for the same reason.

Steve

[Ceeray]

Hehe THX Jetset, do that please, if possibly tiled :)

I managed to do the scaling by myself (lots of freeware D/L + trying)


but tiling is the problem now.

If youre gonna do templates for F-5 canopy , that would be great!!! Wingroots seem to be also a bit diffenrent from eachother.

Also what you said about upping a wing a bit.. How about installing those servos either in the fuselage or putting then on upper side of the wing....?

[T_MECO]

T-MECO - Sorry to hear the first flight was less than successful. I knew the T-38 would be hotter than the F-18 due to the higher wing loading and lack of strakes, but I have high hopes it will still be a parkflyer. To tame the T-38 down a little, I have two suggestions for you:

1) Set the flaperons at 10 degrees for takeoff, and if you're flying in a small field leave the 10 degrees flap in the whole flight. This really helps slow down the F-18 Park Jet and I think it will work well here, too.

2) Enable elevator-to-flap mixing so that full up elevator input drops the flaperons about 15 degrees. This adds additional lift during turns and landing flare that helps compensate for the small wing.

Note that I intentionally raised the wing on the fuselage of this design relative to the real T-38. The reason for that was to provide some flap clearance for belly landings. If the wing were in the scale position near the bottom of the fuselage, you wouldn't be able to land with flaps since it would strip the servos... :eek: I also raised the horizontal tail a little for the same reason.

Steve

Thanks for the suggestions. I will incorporate them. I'll have this plane up by this weekend and give you a status report.

[Spinner]

Pretty big differences in nose length and shapes.

[Spinner]

Steve,

A couple of pics of the end of the line-- the F-20 during 1982 maiden flights at Edwards. Very impressive airplane, but came along when the Air Force was already thinking Advanced Tactical Fighter, which became the F-22.
Gorgeous airplane! :)

[Spinner]

Another

[jetset44]

Steve,

A couple of pics of the end of the line-- the F-20 during 1982 maiden flights at Edwards. Very impressive airplane, but came along when the Air Force was already thinking Advanced Tactical Fighter, which became the F-22.
Gorgeous airplane! :)

Got 3-View? :D

[STaNgXs]

does anyone sell a built kit of that f-15?

[Spinner]

Steve,

Your wish is our command--gonna take a long time to pay your favors back! :)

This bird's notables are the unusual LEX shape, single engine, ram air intake at base of vertical, and flattened "duck bill" nose X-section. Go to it, Coach!

Joe

[DCobra]

I just thaught I'd copy this from the F18 park thread

Steve's Beer Fund ;)
Paypal account address: jetset44@verizon.net

Mike
Good thinking Mike. I recommend anyone building these models kick in a few bucks or whatever you can contribute to keep Steve in Depron/FFF and electronics. Oh yeah, he needs some good dustmasks too :eek:

[jetset44]

Here are the parts necessary to convert the T-38 Park Jet to an F-5 Park Jet. These consist of a new canopy (that is interchangeable with the T-38 canopy), new wing strakes, and balsa missile rails. I've posted previews below to show how these parts look on the finished model, and a PDF file with the full scale tiled templates. Note the new canopy is a bit thin forward and might need some reinforcement. I kept this shaping both so the canopy would be interchangeable with the T-38 and so the battery in the forward fuselage can be easily accessed.

Enjoy!

Steve

[jetset44]

Steve,

Your wish is our command--gonna take a long time to pay your favors back! :)

This bird's notables are the unusual LEX shape, single engine, ram air intake at base of vertical, and flattened "duck bill" nose X-section. Go to it, Coach!

Joe

Thanks, Joe! Boy, the F-20 won't be a simple conversion kit like the F-5--it will take a significant redesign of the aft fuselage to make it look right...

Steve

[Spinner]

Steve,

You are amazing! Now here come all the "Aggressor" color schemes! :)

[jetset44]

Hehe THX Jetset, do that please, if possibly tiled :)

I managed to do the scaling by myself (lots of freeware D/L + trying)


but tiling is the problem now.

If youre gonna do templates for F-5 canopy , that would be great!!! Wingroots seem to be also a bit diffenrent from eachother.

Also what you said about upping a wing a bit.. How about installing those servos either in the fuselage or putting then on upper side of the wing....?

Ceeray,
As requested, here are the T-38 parts templates scaled 120% and tiled onto 5x5 pages. I didn't do anything but scale everything up, so you'll need to make adjustments for the foam thickness when you build it.

Regarding the flaperon servos, it's not the servo arms hitting the ground I'm worried about--if the airplane lands on the flaps it could strip the servos regardless of where they're located!

Steve

[DCobra]

:D Steve,

You are amazing! Now here come all the "Aggressor" color schemes! :)

Hehe...sounds like a mission for the black sturdyboard I've been saving for the F-5/T-38 release. Planning for the "Top Gun" aggressor. Now all we need is a Park-Jet F-14 for some real park shootouts! :p

[Kerberos]

Hi,
is anyone interested in a F-20 3View in dxf-format ?

[jetset44]

Hi,
is anyone interested in a F-20 3View in dxf-format ?

ABSOLUTELY! I mean, PLEASE! ;)

[Kerberos]

ok ok :-)
give me 5 Minutes

[Kerberos]

ok,
here it is.

F-20 3-View DXF-Format (http://kerberos.rchomepage.com/f-20%203-view.dxf)

I think you have to resize it, because its an DXF-export from Micrografx Designer, i'm not into Autocad.

[jetset44]

ok,
here it is.

F-20 3-View DXF-Format (http://kerberos.rchomepage.com/f-20%203-view.dxf)

I think you have to resize it, because its an DXF-export from Micrografx Designer, i'm not into Autocad.

Worked great--thanks!

[Kerberos]

no problem,
hope it helps, it's not a 'real' plan ... only a 3-View

[Ceeray]

Sheehs, this speed in which everything starts moving forward is sometimes unnerving on this board.. you´ll never know how much each visit on these boards will hit your wallet in form of " I WANT THAT TOO".. :D

Keep up the good work.

BTW, I didn´t manage to get sleep because I was tinkering in my mind how to make more curvature into the engine intakes .. Thought about adding another 2 centimeters on both sidepanels, then curving it inside and cutting the edge straight . Then join them with upper and lower plate, which also have to be modified.

Easier way would be adding layered depron in the corner and then sand it into form... hmm also could use that as strengtener, balsa not needed.. And make another piece of intake from 3mm curved depron..

Will post results as soon as I have started.. ;)

BTW who makes French Rafale? I know you Americans don´t like French very much now (freedom fries.... :rolleyes: ) but the plane is so sexy.... :p

[Ben_E]

Thanks Steve for the F5 Ad-ons!!

Things are progressing so fast here..... and last night I was thinking that there must be a way to use these tecniques and some creativity and try to come up with a F-14 Tomcat with possibility to swing the wing. That would have been awsome!!!

Ben_E

[DBa]

BTW who makes French Rafale? I know you Americans don´t like French very much now (freedom fries.... :rolleyes: ) but the plane is so sexy.... :p

Here's for u.

http://uscaero77.free.fr/_avion/rafaleyd/rafale1.jpg

and the DXF plan:

http://marcelluswallace.free.fr/images/avion/rafale/rafale400.zip

Cheers,

DB.

[DCobra]

Thanks Steve for the F5 Ad-ons!!

Things are progressing so fast here..... and last night I was thinking that there must be a way to use these tecniques and some creativity and try to come up with a F-14 Tomcat with possibility to swing the wing. That would have been awsome!!!

Ben_E

Im reading a fiction book right now with a picture of an F-14 on it, and I swear it looks like the perfect candidate for Steve's building techniques.
The painting looks like it was sanded in all the same places we've been sanding on Steve's parkjets!http://www.booksamillion.com/bam/covers/0/44/914/932/0449149323.jpg
The swing-wing operation shouldn't be too difficult, it's already been done by Green Air Designs and others I think.

Probably the hardest thing about that aircraft would be the wide fuselage aft of the cockpit and hand launches.

I'd love to see plans for one, but I wondr if it would be a bit too heavy for the GWS 350C basic setup?

Lol...anyways, I'm starting to fall behind...still need to build the F-15 which I have parts cut for, and I'm 1/4 way through building the X-29.

Maybe I'll build the F-5 and hang it up for display until I have electronics available for it.

[RNAF]

Cool!
I like it that you can download add-ons :) Gr8!
I wonder how Jetset44 makes these planes... I want to try to make a Harrier :)
I know it's been done before but usually they weren't really scale.

Dave

[Spinner]

Kerberos ,

Thanks a million for the F-20 lines! :)

Ben_E and DCobra,

I'm with you guys--an F-14 (and F-22) is what we REALLY want! (Ain't this fun? We're so blessed to have a guy like Steve give so much of his time and talent to us. :)

Joe

[empeabee]

you guys forced me to go BroadBand - now I need to go out and buy a new HardDisk - and I can't do anything in the house because of the new Post Emails :D :D
Mike

[Ben_E]

Kerberos ,

Thanks a million for the F-20 lines! :)

Ben_E and DCobra,

I'm with you guys--an F-14 (and F-22) is what we REALLY want! (Ain't this fun? We're so blessed to have a guy like Steve give so much of his time and talent to us. :)

Joe

How about controls on a F-14? Ailerons might be difficult to do because of the swing-wing – and I'm not sure if elevons would give enough authority...

Any thoughts?

Ben_E

[RoverTomcat]

How about controls on a F-14? Ailerons might be difficult to do because of the swing-wing – and I'm not sure if elevons would give enough authority...

Maybe two servos that sit inside the fuse (on the wings), connected to the ailerons via flexible pushrods? This way, the servos would always be on the same relative position to the ailerons, as they swing back and forth with the wing halves...

:rolleyes: Mmmmmh.... F14.... Yummy....

Best regards - Paco

[Ben_E]

Maybe two servos that sit inside the fuse (on the wings), connected to the ailerons via flexible pushrods? This way, the servos would always be on the same relative position to the ailerons, as they swing back and forth with the wing halves...

:rolleyes: Mmmmmh.... F14.... Yummy....

Best regards - Paco

I downloaded a dxf file from the net and have had a look at it and I'm afraid that ailerons connected to the wing inside won't work. Not enough space in the fuse or to be more correct in the shoulder of the wing. It would have given good control for slower flight but I'm not sure how it would work when the wing is in swept back position.

How is it done with the Green Air design?

Ben_E

[Ben_E]

You can get addicted to this :D :D

GAD pictures:
http://www.rcelectricflight.com/F-14%20Biuld%20(24).JPG
http://www.rcelectricflight.com/F-14%20Biuld%20(25).JPG

Maybe the GAD build manual (http://www.rcelectricflight.com/F-14%20%20Tomcat%20WEB%20manual.doc) will reweil something?

Ben_E

[empeabee]

How about controls on a F-14? Ailerons might be difficult to do because of the swing-wing – and I'm not sure if elevons would give enough authority...

Any thoughts?

Ben_E
Closed loop round pulleys on piviot point?
Thats how Victorian Automata do it.
Mike

[tolladay]

BTW who makes French Rafale? I know you Americans don´t like French very much now (freedom fries.... :rolleyes: ) but the plane is so sexy.... :p

Not all americans have put their heads in the sand. Take a look at this thread; its actually about an F-18, but then the designer started kicking out some other designs. I guess it's not a Rafale, but a Grippen sure looks close from this side of the pond. Should be easy to modify into a Rafale shape.

http://www.rcgroups.com/forums/showpost.php?p=2985893&postcount=1938

I know it's not an edf, but a pusher. It's also a little larger, designed around the GWS 350 size motor. I guess it does high alpha maneuvers pretty well with that canard.

[Spinner]

DCobra,

Great color scheme candidates for Steve's F-5 version of the model are the Air Force/Navy/Marine F-5E Aggressors that were glamour kids of the "Top Gun" enemy forces in the mid 70s. :)

Over 80 of these babies were used specifically for the role. Here's a shot of an Air Force Aggressor formation with prescribed color schemes known as (front to back): "Snake", "Patches", "Ghost", and "Lizard."

These airplanes were all F-5Es, and I've included a 3 view showing the unique "double delta" LEX that this particular version had, but probably only a real scale nut would notice the difference from the F-5A!. :) In any event, a really small change to Steve's LEX lines for the model.

Send pics!
Joe

[Spinner]

Ben_E,

I don't know flip about modelling roll control devices, but I wonder how difficult it would be to try and put in the upper wing spoilers used for roll control on the airplane with the wings forward? Anyone have experiences with spoilers on models?

Thanks,
Joe

[Levi Jordan]

Joe,

Spoiler control is fine at higher speeds, but I think that at the slow speeds of Park style planes the effectiveness would be reduced.

That GAD F-14 is made to be a bullet! I've seen the videos of it and it scoots! The taileron control seems to work well on faster models, but I think that with the lack of roll leverage and slow speeds of the park jet style aircraft, it would just add too much drag, and also be ineffective at slow speeds..

A park f-14 would need to have dual aileron servos mounted in the wings, and then the classic full flying stab for elevator control. The trick is using some smart building techniques to keep the weight low... so that it's still a park jet and not a park rocket :D

[jetset44]

OK, OK, OK, OK, you guys talked me into letting the cat out of the bag----I started work on an F-14 Park Jet last week!! Yes, it is an excellent candidate for these construction methods. It will use all the construction methods of the other park jets along with a built-up 1/8" light ply box swing wing mechanism that pivots on .21" carbon rods and aluminum tube bearings. I've seen the Green Air F-14 and like Levi said it's a screamer, so as usual my design will be larger and simpler and intended to be a quick and easy true parkflyer.

Although I'm a big fan of flaps on the Park Jets, I actually have high hopes that tailerons only will provide adequate control on a Park Jet F-14--especially if I upsize them a bit. That will really help keep the model simple and light. I've also got a few other tricks up my sleeve to help the airplane transition well as the wings sweep... Stay tuned!

Steve

[Spinner]

Steve,

You and Levi are making this a Xmas to remember (especially for depron salesmen!). :) :)

[AceMigKiller]

Judas Priest! An F-14!?

I love it! Made a model from another thread, so I've actually got some 'Cat Experience, if you need any in-flight data or anything let me know! The only thing I couldn't get to work just right is the swing wings...Been a few months since I've touched my
F-14 but I guess I could get back into it to help JetSet44 get his into plan form faster :) (Man, is this guy crazy or what!?) just kidding!
Good luck,
Victor

[Ed Waldrep]

Tailerons should be fine on an F-14...look how far apart they are and how big they are. They work fine on the Wattage F-22, lots of authority. Maybe you wont get 4 rolls per second but that looks silly anyway.

[gearup]

what a neat way to tackle a complex model... I wonder when someone is going to attempt a Lear Jet park flyer

[Levi Jordan]

:d!

[Ben_E]

OK, OK, OK, OK, you guys talked me into letting the cat out of the bag----I started work on an F-14 Park Jet last week!! .....
Stay tuned!

Steve

Well I guess your bag is gonna be full of suprises this x-mas :D :D :D
You are awsome Steve!

And we will stay tuned - ever thought of how people would feel if the rcgroups server went down? :eek: :eek: :eek: - nightmare!!!

Ben_E

[edkoz]

Steve:

I noticed that you posted the plans for the T38 in a new thread. Are you going to do the same with the Gripen plans?

By the way, thank you very much for the T38, paypal coming shortly

Ed

[Spinner]

Steve,

Like everyone else I can’t wait for your F-14 design!! :) Hope you start a new thread on it.

Would like to share some info on the F-14 roll characteristics that might influence your design. Knowing that we’re shooting for a low wing loading, highly maneuverable park flyer with high alpha capability, I’d like to pass on some declassified comments from our NASA/Navy evaluation of the airplane. This comes from about 5 years of wind-tunnel tests, free-flight model tests, and airplane flight tests.

At high-speed, low alpha conditions, the F-14’s rolling tails provide more than enough roll control, and the airplane roll response is outstanding. Also, if the pilot jerks the stick back in a symmetric “Cobra”-like maneuver, the airplane responds very well. However, at high alpha above about 20 degrees at low speeds, use of the rolling tails can make bad, bad things happen! :(

When the NACA first invented the all-moveable horizontal tail for roll control on supersonic aircraft, they noted that, for some geometric tail configurations, the adverse yawing moments produced by deflecting the tails for roll could overpower the rolling moments, resulting in unexpected control-induced departures and spins.

As Ed Waldrop points out, the tails on the F-14 are huge, located outboard, and in proximity to the verticals (compare to the F-18). Unfortunately, this is one of those bad configurations for rolling tails at high alpha. The F-14 was the last high-performance fighter designed without digital controls to automatically mix lateral control surfaces as a function of alpha (in contrast to the F-15, F-16, F-18, and F-22). To make a long story short, when differential tail input is made via lateral stick for roll control at high alpha, the airplane reaction is to initially roll in the intended direction, but the nose will rapidly yaw off in the opposite direction due to the adverse yaw, followed by a roll departure in the other direction! :( This is one of the worst cases of adverse yaw seen on current fighters.

The problem is made worst by the fact that the F-14 has a flat, unrecoverable spin (over 20 F-14s have crashed in flat spins)—the scene in “Top Gun” is pretty accurate! Imagine yourself stting and facing outward on a 25-foot merry go round, turning at one revolution every second or so—if you’re in the F-14 cockpit, that translates to over 8 “gs” eyeballs out!! Some Navy pilots who accidently got into the flat spin were lucky enough to get to the ejection handle—after many spin turns and excruciating pain.

What F-14 fleet pilots (clever and talented guys!) adapted to in normal flight was using “cross controls” to roll the airplane at high alpha—that is, give left stick and right rudder to roll to the right! :) All of our flying model work showed that the best way to get the airplane into the deadly flat spin (especially with the wings forward) was to pull the stick back, then give full lateral stick and wait one turn—you’re there! NASA and the Navy came up with a control system solution that senses lateral stick inputs and automatically phases in rudder as the primary roll control, and phases the tails out at high alpha. Called the Automatic Rudder Interconnect, or ARI, its actions are transparent to the pilot. System has now been implemented in fleet aircraft with the new digital flight control system. :)

All of this might be of interest to you if you intend for lateral control for the model to be only rolling tails. I’m suggesting that some consideration of flaperons, or at least rudders, might be in order.

Hope I’m not boring hell out of you with these stories (factoids turning into hemorrhoids?) If so, just say stop.

Here’s a picture of our NASA/Navy test airplane during a symmetric Cobra maneuver.

Thanks, Coach! :)
Joe

[GaryRC]

"ever thought of how people would feel if the rcgroups server went down?"
I'd pack up a U-Haul full of new servers and head to Oregon. :D :D :D

"Hope I’m not boring hell out of you with these stories" Spinner - I live for this stuff! It's 'The real deal'. Keep 'em coming!

- Gary

[jetset44]

Fascinating insight, Spinner! Thank you very much for sharing these thoughts. And of course you're not boring us--as Gary said, "We live for this stuff!" ;) We wouldn't be surfing this forum if we didn't!

Your comments have definitely affected my thinking of the F-14 Park Jet control system. To me a park jet that doesn't handle high alpha well is just....well....not a park jet! Adding rudders may be the easiest solution, but my experience on the F-18 is that adding rudders to a twin-tailed park jet is a pain in the rear since you have to run two flex cables from the servo to the two rudders (which is both heavy and sloppy). My other thought was to imbed servos into each wing to drive flaperons (like on the T-38)--which offers additional low-speed benefits but adds the weight of two servos and linkages. Unfortunately, both options add weight to an airplane that will already be weight-challenged due to the heavy swing-wing mechanism...

This design will certainly be a challenge--but that's the best part! I love a good engineering design challenge. :D

Steve

[jetset44]

Steve:

I noticed that you posted the plans for the T38 in a new thread. Are you going to do the same with the Gripen plans?

By the way, thank you very much for the T38, paypal coming shortly

Ed

Yes, I will start a new build thread for the Gripen once the plans are ready to post.

Steve

[TBolt]

jetset44,
Your killing me, how am I supposed to keep up with all these great designs!
Anyhow thank goodness for my son AceMigKiller (Victor), now if I could only get my other son into this.

[tolladay]

Spinner,
Thanks for the F-14 info; way cool. I have a brother-in-law who used to fly hot rods for the navy back in the gulf war. I always suspected he was a good pilot, and now I'm sure. And I thought it was tricky trying to land a plane at 100+ (what ever is the stall speed for that flying pig anyway?) mph into an area the size of a tennis court that can move up and down as much as 60 feet.

[DCobra]

Yeah!!! I can't wait to see the F-14 design you come up with Steve! :D
The way you are cranking out these planes is unreal! I can't even build 'em as fast as your designing AND building! IMHO I think YOU should be the winner of the jet design contest... :D Thanks again for contributing these jets to your fellow fliers...I know I would still be buying WWII warbirds if you hadn't started this trend of Depron park-jets. (Nothing wrong with WWII warbirds...I just love the modern jets more!)

Spinner, great info on the F-5 aggressors and the F-14. I love hearing that stuff and seeing whether the real-world performance translates down to the parkflyer scale. Keep it coming!

[Ceeray]

Hmm.. anyone checked out the back of the F-5a and F-5e versions? Seems that F.5e has a bit different upper fuselage.

I prolly make F-5a version, but upper fuselage still needs some more shaping I think. Couple of laminated depron sheets will do the job and some sanding.

Also notice that the canopy is not as wide as fuselage , so there is also room for little improvement. Thought about adding another strip inside side panels and sanding it down to show curvature.

[empeabee]

Joe,

Spoiler control is fine at higher speeds, but I think that at the slow speeds of Park style planes the effectiveness would be reduced.

That GAD F-14 is made to be a bullet! I've seen the videos of it and it scoots! The taileron control seems to work well on faster models, but I think that with the lack of roll leverage and slow speeds of the park jet style aircraft, it would just add too much drag, and also be ineffective at slow speeds..

A park f-14 would need to have dual aileron servos mounted in the wings, and then the classic full flying stab for elevator control. The trick is using some smart building techniques to keep the weight low... so that it's still a park jet and not a park rocket :D
Oh I don't know - Last year some one built a Wright Flyer 1 model, didn't want to do wing warping, so he use spoilers on lower wing & reported it flew GREAT.
Mike

[empeabee]

OK, OK, OK, OK, you guys talked me into letting the cat out of the bag----I started work on an F-14 Park Jet last week!! Yes, it is an excellent candidate for these construction methods. It will use all the construction methods of the other park jets along with a built-up 1/8" light ply box swing wing mechanism that pivots on .21" carbon rods and aluminum tube bearings. I've seen the Green Air F-14 and like Levi said it's a screamer, so as usual my design will be larger and simpler and intended to be a quick and easy true parkflyer.

Although I'm a big fan of flaps on the Park Jets, I actually have high hopes that tailerons only will provide adequate control on a Park Jet F-14--especially if I upsize them a bit. That will really help keep the model simple and light. I've also got a few other tricks up my sleeve to help the airplane transition well as the wings sweep... Stay tuned!

Steve

Do you ever sleep ? :D
Mike

[empeabee]

Well I guess your bag is gonna be full of suprises this x-mas :D :D :D
You are awsome Steve!

And we will stay tuned - ever thought of how people would feel if the rcgroups server went down? :eek: :eek: :eek: - nightmare!!!

Ben_E

The whole Internet would speed up 100% :D :D
Mike

[empeabee]

Steve,


Hope I’m not boring hell out of you with these stories (factoids turning into hemorrhoids?) If so, just say stop.

Here’s a picture of our NASA/Navy test airplane during a symmetric Cobra maneuver.

Thanks, Coach! :)
Joe

You are definitly NOT boring ME - keep it up - most interesting.
Mike

[empeabee]

Fascinating insight, Spinner! Thank you very much for sharing these thoughts. And of course you're not boring us--as Gary said, "We live for this stuff!" ;) We wouldn't be surfing this forum if we didn't!

Your comments have definitely affected my thinking of the F-14 Park Jet control system. To me a park jet that doesn't handle high alpha well is just....well....not a park jet! Adding rudders may be the easiest solution, but my experience on the F-18 is that adding rudders to a twin-tailed park jet is a pain in the rear since you have to run two flex cables from the servo to the two rudders (which is both heavy and sloppy). My other thought was to imbed servos into each wing to drive flaperons (like on the T-38)--which offers additional low-speed benefits but adds the weight of two servos and linkages. Unfortunately, both options add weight to an airplane that will already be weight-challenged due to the heavy swing-wing mechanism...

This design will certainly be a challenge--but that's the best part! I love a good engineering design challenge. :D

Steve

Saturn 4.4g servos?
Mike

[Ralph A. D'Amelio]

Hey guys, I think this thread is weaving abit. FWIW, I think we are moving away from the T-38 by going off into adjcent tangents. Having built and flying a 32"ws T-38 of my own I know you will find it to be a sleek, fast, agrressive and beautifull airplane in the air. I'm just waiting to get my depron in to build another based on 3Dfoamys plans.

I was hoping by now someone would be building and flying the jetset44 T-38. Anyhow just my 2 cents and I will shut up.

Ralph

[Spinner]

Ralph,

It's all Steve's fault! :) Every time he coughs we get a new hot topic! Steve needs a secretary responsible for starting new threads.

Joe

[Photon]

We also need a web page with links to all these threads. I'm getting lost with all these thread subscriptions. :-)

[Ralph A. D'Amelio]

Yes, yes, it's Steve's fault! ooh, I said I was going to be quiet. ;)

[jetset44]

Good point, Ralph--this thread has gone off topic a bit... There just seems to be so much pent up excitement over these Depron jets that it's easy to get distracted. That's certainly why I've been cranking 'em out the past few months. I've been flying RC airplanes for 24 years now and have ALWAYS wanted to have my own parkflyer-type jet fighter models, and now the technology has finally arrived to make it happen. And happen easily. Thus, you're seeing 24 years of pent up frustration exploding out of me! That's why I've done 4 jet fighter designs in the past four months. And while I don't expect to keep up this pace, I've got TONS of ideas for other cool projects floating around inside my head just itching to get out. Maybe I'll target one new airplane every two months from now on.... :D

Sooooo, has anyone out there begun construction of a T-38 Park Jet yet? I'm dyin' to hear how it comes together!

Steve

[T_MECO]

Sooooo, has anyone out there begun construction of a T-38 Park Jet yet? I'm dyin' to hear how it comes together!

Steve

My plan is almost back together. Itlooks kind of funny half painted and half blue fanfold. The crash broke clean at the base of the the forward fusalege. the rest of the plane looks unscratched. Weather permiting, this Saturday I will give her a toss.

By the way, how do you attach pictures in adobe to be tiled? where is that option in adobe?

-t-meco

[RNAF]

Good point, Ralph--this thread has gone off topic a bit... There just seems to be so much pent up excitement over these Depron jets that it's easy to get distracted. That's certainly why I've been cranking 'em out the past few months. I've been flying RC airplanes for 24 years now and have ALWAYS wanted to have my own parkflyer-type jet fighter models, and now the technology has finally arrived to make it happen. And happen easily. Thus, you're seeing 24 years of pent up frustration exploding out of me! That's why I've done 4 jet fighter designs in the past four months. And while I don't expect to keep up this pace, I've got TONS of ideas for other cool projects floating around inside my head just itching to get out. Maybe I'll target one new airplane every two months from now on.... :D

Sooooo, has anyone out there begun construction of a T-38 Park Jet yet? I'm dyin' to hear how it comes together!

Steve

*Trying to get all this in his advantage*

Hey Steve *blinks eyes* could you make an AV-8B Harrier for us? *puppy face*

Thank you,
Dave :D

[Ceeray]

Sooooo, has anyone out there begun construction of a T-38 Park Jet yet? I'm dyin' to hear how it comes together!

Steve


I have cut almost all parts, left all uncut which I think needs modifying.
Scale 120% from original and Boy! is this thing BIG!!!

Lenght will be over 130cm... I´m running on my second sheet of 6mm depron already...

Hope my micro-15 will be enough. This model is big enough to insert rectracts....

I will start assembling prolly next saturday, tomorrow and day after that I´ll be busy.

[edkoz]

Not a lot of progress yet but just a note to let you know that I cut it out late late last night and will start the build tonight or tomorrow.

Ed

[DCobra]

Ahh....parts...droool.
I'm tempted to start my own cutting now after that pic!
Im curious about the block of bluecor... do you start with a solid block (laminated of course :D ) and sand to shape instead of cutting out 10 or so identical nosecones?

I'd love to try that but pretty sure I would end up with a pile of foam dust and a worthless nosecone :(

Keep us posted Edkoz!

[edkoz]

Ahh....parts...droool.
I'm tempted to start my own cutting now after that pic!
Im curious about the block of bluecor... do you start with a solid block (laminated of course :D ) and sand to shape instead of cutting out 10 or so identical nosecones?

I'd love to try that but pretty sure I would end up with a pile of foam dust and a worthless nosecone :(

Keep us posted Edkoz!

I start with a laminated block, glue the template on it and rough shape it on the bandsaw, then sand.

I started to peel the backing off the bluecore and one side comes off easy but the other is absolutely horrible :mad: . I'll try a couple more and if I still have the problem I'll just cut some depron pieces.

Ed

PS: I solved the bluecore backing problem. When I cut the blanks, I cut them on the band saw. This must have fused the paper to the foam on the cut edges. I just took my xacto knife and re cut about 1/16 off all the sawed edges and now the film backing comes off much easier, :)

[empeabee]

Good point, Ralph--this thread has gone off topic a bit... There just seems to be so much pent up excitement over these Depron jets that it's easy to get distracted. That's certainly why I've been cranking 'em out the past few months. I've been flying RC airplanes for 24 years now and have ALWAYS wanted to have my own parkflyer-type jet fighter models, and now the technology has finally arrived to make it happen. And happen easily. Thus, you're seeing 24 years of pent up frustration exploding out of me! That's why I've done 4 jet fighter designs in the past four months. And while I don't expect to keep up this pace, I've got TONS of ideas for other cool projects floating around inside my head just itching to get out. Maybe I'll target one new airplane every two months from now on.... :D

Sooooo, has anyone out there begun construction of a T-38 Park Jet yet? I'm dyin' to hear how it comes together!

Steve
Blame Bill Gates for facilitating TurboCad
& McDonalds for ramping up depron sheet production ;) :D
Mike

[DCobra]

Blame Bill Gates for facilitating TurboCad
& McDonalds for ramping up depron sheet production ;) :D
Mike

Don't forget to blame Al Gore for inventing the internet and therefore providing us this awesome forum :p :p :p

@Edkoz, thanks for sharing that technique :D That will defnitely cut my build time down, never thought about doing it that way!

[edkoz]

Don't forget to blame Al Gore for inventing the internet and therefore providing us this awesome forum :p :p :p

@Edkoz, thanks for sharing that technique :D That will defnitely cut my build time down, never thought about doing it that way!


Let's not forget those damn Wright brothers.

[DCobra]

Let's not forget those damn Wright brothers.

Damn Wright... :D

[edkoz]

I extended the foam strips on the fwd fuselage sides with some 3/8 balsa triangle to go all the way to the end for a little added strength when joining the fwd fuselage bottom to the aft fuselage bottom.

Ed