HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 28, 2011, 10:13 AM
Slipping the Surly Bonds
dz1sfb's Avatar
Attica, MI
Joined Dec 2006
10,024 Posts
This is a good cheap motor that you can run on 3s with a 7x5 or 7x6 prop that will give you excellent performance for the buck. http://www.hobbyking.com/UNITEDHOBBI...idProduct=4321

Ken
dz1sfb is online now Find More Posts by dz1sfb
RCG Plus Member
Latest blog entry: Mini H Quad Project
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 30, 2011, 09:36 PM
Registered User
Joined Oct 2007
6 Posts
guys,
please help, i have these items :

- Turnigy 2632 Brushless Motor 3400kv ( http://www.hobbyking.com/UNITEDHOBBI...idProduct=8480 )
-TURNIGY Sentry 40amp Speed Controller ( http://www.hobbyking.com/UNITEDHOBBI...idProduct=3729 )
- ZIPPY Flightmax 2200mAh 3S1P 20C ( http://www.hobbyking.com/UNITEDHOBBI...idProduct=6306 )
- prop TGS Sport 4.75x4.75E Precision propeller( http://www.hobbyking.com/UNITEDHOBBI...idProduct=7933 )

does these items fit on this Prime Jet8? or i have to use smaller battery (well, i have 800mah and 1050mah 3cells batts) ?

thank you.
regards
Irvan
flytosky is offline Find More Posts by flytosky
Reply With Quote
Old Jul 02, 2011, 07:32 AM
RC Addict
anatoly's Avatar
Falls Church, VA
Joined Jul 2006
2,238 Posts
Irvan,

You could use that gear, you just have to build the plane large enough to carry it. I would say go with the 28" or 32" version, definitely no smaller. Also, you should probably not use smaller packs, unless you are certain that they can handle the amp draw of your motor and prop combination.
anatoly is offline Find More Posts by anatoly
Reply With Quote
Old Jul 02, 2011, 01:28 PM
nickeast
Stuart,FL
Joined Mar 2009
557 Posts
guys,
I am using this motor....

http://www.headsuprc.com/servlet/the...00-Zoom/Detail

I am using this on my plane and it screams.... I use the reccommended prop and ESC. (everything is on this page with specs... thses folks do a great job with the specs) My plane is a 32" span and all up weight is about 16 ozs. I launch using a "frisbee" toss... hold the plane in your right hand along the leading edge, run the motor up, and side arm it up.... no chance of the prop hitting you and it will go vertical out of sight. See post 818 on this thread....
nickeast is offline Find More Posts by nickeast
Reply With Quote
Old Jul 09, 2011, 06:24 PM
Just an Earth bound misfit - I
vanderbrander's Avatar
Canada, ON, L'Orignal
Joined Nov 2010
1,066 Posts
Quote:
Originally Posted by flytosky View Post
guys,
please help, i have these items :

- Turnigy 2632 Brushless Motor 3400kv ( http://www.hobbyking.com/UNITEDHOBBI...idProduct=8480 )
-TURNIGY Sentry 40amp Speed Controller ( http://www.hobbyking.com/UNITEDHOBBI...idProduct=3729 )
- ZIPPY Flightmax 2200mAh 3S1P 20C ( http://www.hobbyking.com/UNITEDHOBBI...idProduct=6306 )
- prop TGS Sport 4.75x4.75E Precision propeller( http://www.hobbyking.com/UNITEDHOBBI...idProduct=7933 )

does these items fit on this Prime Jet8? or i have to use smaller battery (well, i have 800mah and 1050mah 3cells batts) ?

thank you.
regards
Irvan
Definitely too much for this size aircraft. With that motor and 4.75x4.75 prop you'll be pulling over 40 amps (+400w). It's a pretty powerful motor and I don't think a 40amp ESC is going to take it. You would need to build a 32"-36" version - even then it will scream.

This is a really good motor for a 32" size fun jet.

http://www.hobbyking.com/hobbyking/s...idProduct=5246

Perfect for the battery, ESC and prop you have.

Here's the specs

2200mah 3S, 40 amp mystery ESC, 4.75x4.75 APC prop
34amps, 375w, +750g thrust.

I have a couple on some scratch built fun jets and I can highly recommend them.
vanderbrander is offline Find More Posts by vanderbrander
Last edited by vanderbrander; Jul 09, 2011 at 06:32 PM.
Reply With Quote
Old Jul 19, 2011, 10:55 PM
Registered User
Vechlor's Avatar
Nevada City, CA, USA
Joined Nov 2008
22 Posts
Hey everyone.
I found this thread back in April and have been following it ever since. This is my first scratch built foamie, so I thought I would share my build with everyone now that it's finished. I haven't made a test flight yet, but will soon.

Specs:
22" wingspan
8.7oz (minus prop saver and prop)
hxt500 5g micro servos
gen ace 1000mah 25c 2s lipo
hobbyking blue series 30a bec
turnigy 2730 3000kv motor
4.5x4.5 to 5.5x5.5 tgs props

I started with dollar tree foam board for a test build, it turned out pretty good, light as a feather, but not rigid enough for my taste. Then I tried an old piece of 22x28" elmers foam board (black core), it was dented, scratched in some places but useable and much more rigid, perhaps a bit heavier. The paper backing on both sides is a to remove... I tried many things mentioned on this board to remove the stuff, but in the end, soap and hot water in the tub for a few hours with a wash rag and some elbow grease leaves a nice foam surface. This foam can be found at Ben Franklin Crafts, also the framing department carries double the size boards for a bit less cost, they will even cut it to any size you like.

Long story short, after seeing some pics of the RAF Typhoon F1 jet, I wanted to try a single vert. fin and move the servos inside the fuselage. Some minor mods here and there, I managed to fit everything inside, CG is a tiny bit on the nose minus the prop. Anyway, I'll let these photos speak for themselves.

Thanks for the use of the plans, it was an easy and fun build.
Vechlor is offline Find More Posts by Vechlor
Last edited by Vechlor; Jul 19, 2011 at 11:13 PM.
Reply With Quote
Old Jul 20, 2011, 07:51 PM
Just an Earth bound misfit - I
vanderbrander's Avatar
Canada, ON, L'Orignal
Joined Nov 2010
1,066 Posts
NOt bad for a first scratch build!! A friend once said to me that if it looks good it's going to fly well....and that my friend looks pretty nice...!!!

Good luck on the maiden.
vanderbrander is offline Find More Posts by vanderbrander
Reply With Quote
Old Jul 20, 2011, 08:39 PM
Slipping the Surly Bonds
dz1sfb's Avatar
Attica, MI
Joined Dec 2006
10,024 Posts
I'll second that!

Ken
dz1sfb is online now Find More Posts by dz1sfb
RCG Plus Member
Latest blog entry: Mini H Quad Project
Reply With Quote
Old Jul 25, 2011, 03:04 PM
Registered User
Vechlor's Avatar
Nevada City, CA, USA
Joined Nov 2008
22 Posts
Hey everyone.

Update on the maiden flight last Saturday.

It went pretty bad... First throw at half throttle with some elevator trim and it dropped to the ground after a few feet, saved it! Second try I increased D/R and throttle, a bit better that time but it turned the opposite way while doing a crash dive cartwheel. Broke the fuse in half where it meets the front wing, no other damage. You guessed it, I had my elevons moving in reverse!

Sunday's flight test: Everything glued back together, controls working in the right direction with full travel, I used 3/4 throttle for takeoff. It went up, I made a left turn when all hell brakes loose. Looked like a backwards triple axel with a twist at 30ft in the air before hitting the ground! Nothing broke!

It seems somethings up with my CG... I used the calc from here, also included a picture of my values. Based on those values, my CG is more forward than what the plans show, which would make sense with a tail heavy plane. I moved the battery all the way up and added 13.3g of weight to the nose to balance it.

This week I'll give it another try with the batt and weight at the nose, but any suggestions as to what might be wrong will be most appreciated.
Vechlor is offline Find More Posts by Vechlor
Last edited by Vechlor; Jul 25, 2011 at 06:30 PM. Reason: Added wing loading data including canards.
Reply With Quote
Old Jul 25, 2011, 08:46 PM
Flying high
billwhit's Avatar
Seattle, Wa
Joined Dec 2002
2,263 Posts
Vechlor,
When I built mine I went for the forward swept wing, but I've intended on doing a straight wing version at some point. My FSW flies pretty well so a friend of mine tried doing a straight wing. We never did get his to fly, it was strange. He even handed me the controls to try and I couldn't keep it in the air and CoG wasn't helping. He gave up on it and we never did find out what the problem was. The reason I'm telling this story is that your build has something in common with his...the single vertical stab.

So, I really can't say for sure but I was always thinking that was one variable he had different from stock. I told him to put two, but he wanted it that way. Maybe you need to increase the surface area of it to get away with one? You could try temporarily adding a piece of foam to it to see if it helps. Otherwise I wonder if it maybe needs the dual stabs for stability.

Something to think about anyway. I hope you get it flying, good luck!
billwhit is offline Find More Posts by billwhit
Reply With Quote
Old Jul 26, 2011, 05:46 AM
Registered User
Europe, Switzerland
Joined Oct 2010
97 Posts
Hi folks!

I had one of the first Funjets available, unfortunately, it had a non-planned special-effect with smoke and such after about 45s of "non-WOT"...

I've been thinking about a similar design for quite some time, and visited the PrimeJet for two times already, walking away again because I would've needed to buy everything, which sucks if you already have about 5 unfinished projects lying around, and a sixth one does not really help the motivation...

But...
When I rumbled lately through "uncharted territories" of my working shop, I did find that little jewel, which would fit almost perfectly...
Waypoint W-E2205-36, will produce around 280g of thrust with a 6x4-pusher when in prop-stall and 500g when undisturbed flow... Weight of propulsion-system will get to around 140g, leaves me around 300g to finish the airframe off...
Looking for the FSW-version...

Question...

Did someone weight the airframe after finishing...?
What's the realistic empty weight without components?

Thanks for the help!

Cheers,
Dany
Danyboy is offline Find More Posts by Danyboy
Reply With Quote
Old Jul 30, 2011, 09:24 PM
Just an Earth bound misfit - I
vanderbrander's Avatar
Canada, ON, L'Orignal
Joined Nov 2010
1,066 Posts
Sorry to hear it didn't go so well Vechlor.

I've found with mine the CG margin is very small. If I move the battery any more than +/-0.5" it does one of two things. Too far aft and it pitches up uncontrollably at anything above 1/2 throttle - too far forward and it tends to "tuck under" when down elevator is applied.

A reason may be the relatively short distance between the canard and the CG point. Also, becasue the wing is almost straight with a (relative) slight fwd sweep, the pitch moment is small, making it very sensitive to pitch inputs.

Try a couple of things - decrease your pitch throws to no more than +/- 0.25" and add about 30% expo to your elevators to calm things down. Gradually increase the throws as you gain confidence.

For all my models, I use the same CG calculator to get a rough idea of where the CG should be. Then before I maiden any model (except the big ones), I find a suitable area of long grass and (starting at a low height) give it a throw. With the CG too far aft it will stall tail first. Too far forward and it will nose in. Once you have it right, it should glide from standing height all the way to landing without stalling.

This works for me every time and gives me confidence it's going to fly ok for the maiden flight. Any bad habits it may have after this aren't due to CG issues.

Once you get thru the maiden you can fine tune your CG to suit your tastes.
vanderbrander is offline Find More Posts by vanderbrander
Reply With Quote
Old Aug 14, 2011, 02:23 PM
Registered User
cbr600f2's Avatar
Rochester, NY
Joined Nov 2007
351 Posts
Finally some color

After seeing all the great looking versions lately I was inspired to add some color to the PRIME JET I had built for a friend of mine...of course right after the re-build....yeah I had to re-build her after a failed attempt to teach my friend how to do a snap roll on the buddy box. A combination of too much speed and too little altitiude. She went straight in at about 50-60 MPH nose first. Everything from the wing leading edge forward was destroyed (except for the laminated nose)...

After a new front fuse, I decided to FG with WBPU and added a nice coat of white, then the Monocote Trim sheets. I also added the nasa duct for better cooling and a second wing spar about 3" forward of the first one. I used to have a lot of wing flutter at full throttle dives from altitude. Not any more....this thing still rocks.
cbr600f2 is offline Find More Posts by cbr600f2
RCG Plus Member
Old Aug 14, 2011, 05:50 PM
BOXFUSE KING!
Kronikpilot's Avatar
NO WIND CITY GUAM U.S.A
Joined Jan 2009
976 Posts
Quote:
Originally Posted by Vechlor View Post
Hey everyone.

Update on the maiden flight last Saturday.

It went pretty bad... First throw at half throttle with some elevator trim and it dropped to the ground after a few feet, saved it! Second try I increased D/R and throttle, a bit better that time but it turned the opposite way while doing a crash dive cartwheel. Broke the fuse in half where it meets the front wing, no other damage. You guessed it, I had my elevons moving in reverse!

Sunday's flight test: Everything glued back together, controls working in the right direction with full travel, I used 3/4 throttle for takeoff. It went up, I made a left turn when all hell brakes loose. Looked like a backwards triple axel with a twist at 30ft in the air before hitting the ground! Nothing broke!

It seems somethings up with my CG... I used the calc from here, also included a picture of my values. Based on those values, my CG is more forward than what the plans show, which would make sense with a tail heavy plane. I moved the battery all the way up and added 13.3g of weight to the nose to balance it.

This week I'll give it another try with the batt and weight at the nose, but any suggestions as to what might be wrong will be most appreciated.
....Sorry about the crash. Don't give up on that beautifull work of art, sort things out and let her kiss the sky. Thanks for sharing.

KP.

Quote:
Originally Posted by cbr600f2 View Post
After seeing all the great looking versions lately I was inspired to add some color to the PRIME JET I had built for a friend of mine...of course right after the re-build....yeah I had to re-build her after a failed attempt to teach my friend how to do a snap roll on the buddy box. A combination of too much speed and too little altitiude. She went straight in at about 50-60 MPH nose first. Everything from the wing leading edge forward was destroyed (except for the laminated nose)...

After a new front fuse, I decided to FG with WBPU and added a nice coat of white, then the Monocote Trim sheets. I also added the nasa duct for better cooling and a second wing spar about 3" forward of the first one. I used to have a lot of wing flutter at full throttle dives from altitude. Not any more....this thing still rocks.
...Nice work as always bro, that looks awesome.

ALBRT
Kronikpilot is offline Find More Posts by Kronikpilot
Reply With Quote
Old Aug 14, 2011, 07:16 PM
Registered User
Waltjg's Avatar
Crystal River Fl.
Joined Jul 2008
3,681 Posts
Nice looking planes, sorry about your crash Veclor, interesting what you used for paint, care to expand on that alittle?? Been looking at this build for abit and finishing up another was thinking about building a smaller version, just got a couple of little motors and batteries in so this maybe the guy to try them out on.. Looks like fun.. w.
Waltjg is offline Find More Posts by Waltjg
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log A Mini funjet - type thing ( full fuse ) Prime_8 Scratchbuilt Indoor and Micro Models 168 Nov 18, 2010 01:37 PM
Discussion Prime Cut + 20 KevinSheen Giant Scale Airplanes 1 Jul 27, 2010 07:48 AM
Discussion Yet another Funjet FPV hakuna FPV Talk 0 Jun 02, 2010 10:15 PM
Discussion Another FPV Funjet JohnyGab FPV Talk 21 Jul 30, 2009 10:17 AM
To prime...or not to prime Simon_au Slope 12 Dec 18, 2004 08:04 PM