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Old Feb 01, 2010, 12:56 PM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Aberdeen
Joined Mar 2006
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'Stick and tissue' Mig 17 Fresco for 30mm EDF

Here's my old fashioned stick and tissue freeflight Mig 17 for 30mm EDF. It's 17" span with a target weight around 100g

Here's the plan:



And here is the fuselage taking shape with one of by old Rapier rocket power models (Me-163) alongside for scale comparison.


Not sure if there is much interest in freeflight in this forum but i thought it more appropriate to post here than in the Freeflight forum due to the micro EDF power.

If there is any interest I'll keep the build photos coming.

Steve
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Old Feb 01, 2010, 01:32 PM
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stegla's Avatar
Guernsey
Joined Jan 2002
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Steve, keep the photos coming. Indeed...........I would like to build one myself!

Steve
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Old Feb 01, 2010, 02:53 PM
C130H rules !!!
Bryce From Nice's Avatar
France, Centre, Boulay-les-Barres
Joined Aug 2004
116 Posts
Yes, more pics !

I love those stick n' tissue jets for rapier or micro edf (rc or freeflight). It is real modelling !

I spent hours watching beauties like this one on this site :Mike's flying scale model pages

Steve, do you know any other website on stick n' tissue freeflight jet ?

Bryce.
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Old Feb 01, 2010, 03:44 PM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Aberdeen
Joined Mar 2006
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Bryce,
There are a few of my Rapier jets on Mike Stuarts web site. Mike is a real master when it comes to scale freeflight models and it was his site that got me back into freeflight modelling.

The only other active web site i can think of that specialises in freeflight jets is www.jetex.org . Jetex.org is a great place to visit if you have fond memories of old Jetex rocket motors. It's also the place to go to find out about the more recent Rapier rocket motors. The forum is a bit quiet recently due to supply problems with Rapier meaning that not much building or flying is going on.

If you like vintage stick and tissue jet plans then I've posted links to a few over in the freeflight forum on this very site: http://www.rcgroups.com/forums/showthread.php?t=593492


Steve.. if you are serious about building the Mig drop me an email.. The design is going to be kitted but it would be good to have someone else build a model from the plan to pick up any areas that perhaps are unclear or incorrect. I've picked up a few areas for improvement already but a fresh pair of experienced eyes would pick up more I'm sure.

I was also thinking of doing a R/C option on the plan so any advice on that would be appreciated.

cheers
Steve
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Old Feb 01, 2010, 07:48 PM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
12,419 Posts
Steve, being an "old stick modeler" I just love looking at good work. Yours is superb. I'll have to twist my own arm, one day, and give doculam a try.

Jetex?? My only experience was 45 yrs ago(10yrs old). Using the Jetex 150. After several falures and successes, winter arrived. I got the idea for a rocket powered sled. Bad idea. I lit the fuse, set it on the snow. And it stuck to the snow. The mtr started to psssssttt...and wanted nothing to do with the clamp mount. I had to dive into the snow. I could not see it, just hear it, all over the place.
Finally it stopped. I found many holes in the snow, where it entered and exited. But could not find the mtr. I had to mow several lawns for the mtr and fuel/fuses. I was heartbroken. We had 3 pear trees. In august I climbed one tree to get pears and there was my mtr, wedged between a fork in the limbs. Never flew Jetex again.

Just thought I would share that..

Fuzz
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Old Feb 01, 2010, 08:09 PM
Team30 Micro EDF
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Adelaide, Australia
Joined Apr 2004
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That looks like a micro edf model to me Steve!

Please do post progress photos and the always highly demanded 'maiden' video or photo's!
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Old Feb 02, 2010, 02:06 AM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Aberdeen
Joined Mar 2006
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Good to see you guys are open to old fashioned freeflight modelling

I burned midnight oil and got the starboard wing done last night. The fit up of the wing to the fuselage uses a stub spar extension that locks into a retaining plate. Due to the sweep angle this was one of the trickier pieces of design work and I was 'over the moon' when it fitted up perfectly first time. Such moments are the most rewarding part of own design modelling.. Of course when it does not work out so well it can be a bit frustrating.
Fingers crossed the next wing goes together equally well.

A one wing airplane is not very photogenic so I'll take some more snaps when I get the other one built.

Steve
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Old Feb 02, 2010, 06:38 PM
Grumpy old git.. Who me?
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The second wing came out fine. It's starting to look like Mig 17 now (20g as pictured).....
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Old Feb 02, 2010, 06:50 PM
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Omaha Nebraska
Joined Feb 2006
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I'm so voting to keep this one going. 100 grams, roughly 3.6 oz, what gear are you using? EDF, ESC, Battery, is it freeflight, if it's RC, Receiver, servos?

Gearing my energy to micro EDF at this time and doing lots of testing of gear, airframe weight my big challange. Any specs would be appreciated.

Fred
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Old Feb 02, 2010, 07:04 PM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
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Thanks for the support Fred.

It's looking like I'll come in well under my target weight.

Components are:

AEO 30mm EDF (12.7g)
Flightpower Eonlite 350mAh 2 cell (21g)]
10A ESC (8g)
Timer/progammer (which replaces R/C receiver) (2g)

Latest estimated all up airframe weight 40g

Total all up weight = 83.7g

Thust from the AEO fan is about 70-75g (i've tested it at this) so that gives a very healthy (possibly dangerously high for freeflight) thrust/weight.

I'd guess an RC conversion using 2.5g servos would add about 15g or thereabouts?.. So an R/C version of the model could perhaps still come in below the original 100g freeflight target weight.

Any advice on the best kit to spec for an R/c conversion would be good.

cheers
Steve
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Old Feb 02, 2010, 07:30 PM
It's a spiderweb of knit lines
Souderton Pa. USA
Joined Mar 2002
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Looks great Steve!
What's the intake and exhaust sizes?
I think you'll want to throttle back a bit for free flight, can your timer do that?
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Old Feb 02, 2010, 07:53 PM
Team30 Micro EDF
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Adelaide, Australia
Joined Apr 2004
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Nice stuff Steve.

Mike, it looks like the sizes are around a straight 32mm all the way through.

Enlarging the former holes in front of the motor would be fun to do around now, huh?
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Old Feb 03, 2010, 12:45 AM
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Omaha Nebraska
Joined Feb 2006
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Steve,

Just sitting here thinking about your question on thoughts for RC.

It's really easy to figure on a 2 servo RC setup under 10 grams, even a few years ago I was using the Cirrus micro jewel system, Receiver, ESC (1 or 2 cell available, 7 amp max), 2 servos= 10 gram AUW for the whole system. Now with 2 gram Spectrum receivers, and servos more than 1-2 grams less in weight, probably could figure a 8 gram or less 3 channel RC system (no battery or motors). Figuring that your system already has ESC & timer you might only add 6 +/- grams equipment not counting pushrods and mounting options (1-2 gram max).

I was having great luck with 120-140 sqin wing areas using 40 & 50mm fans on 12mm brushless inrunners, AUW as high a 7.2 oz. I designed a F-16 profile and built 12 of them. They ranged from 6-7.2 oz, on 40mm brushed (GWS), and 40mm, 50mm brushless. These had 4.7-5.5 gram servos, 3 & 4 channel, always only one aileron servo, receivers were 5-7 gram, and the batteries needed to be 3 cell 700-840 mah 10C's. They flew great, fast or slow, landings at high alpha were beautiful.

Fast forward and now you have such a high thrust to weight system and under 100 gram AUW airframe (way under 1/2 the weight, 1/2 to 2/3's the thrust. Your plan would be so easy with RC, I'm guessing 60-80 sqin wing area would be fast, and at 80 sqin, float well enough at lower speeds for easy landings. For all out speed, you might get away with 50 sqin or so.

I have not printed out your plan to check it out yet as I'm on a netbook right now, so I can't even read the title/spec data. I'm in love with the whole idea of 30mm 'shrunk' down into the 12-16 inch wingspan size. Truely micro! My 40-50mm F-16 was 20" WS and with the new brushless 30mm EDF's out now, I could change material thickness, lighter battery, and still fly the same size airframe. That would be no fun, it's too large (maybe just not a challange anymore). My challange is to get the plane as small as the gear I can get, if I can still have a controllable, durable, and fun airframe.

Look at the success of the whole Horizon Hobby PNP airframes using the 3.9 gram 6400 board. They sell like hotcakes, everyone love them. 1 ounce, 15" WS, micro Sukoi's, P-51's, Cubs, Cessna's, etc. With 1.5-1.7 gram servos in the 2.5 ozin torque range, with 6 channels on the board, and brushless ESC convertable, the only limit now is that they are only Single cell compatable. However that may change, soon.

It might be worth taking your plan, making a very quick depron profile version at a given wing planform size and shape, even add some dead weight if needed, and test fly the heck out of it.

Whatever you are doing it is great. Got a little long winded, but hope it give some fuel for thought.

Fred
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Old Feb 03, 2010, 01:44 AM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Aberdeen
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Quote:
Originally Posted by mcross View Post
Looks great Steve!
What's the intake and exhaust sizes?
I think you'll want to throttle back a bit for free flight, can your timer do that?
Inlet is a straight 32mm tube with a nicely curved inlet lip. The outlet tapers from 30mm to 26mm then has a short parallel 26mm section. On ethe AEO fan due to the big 17mm outrunner 26mm is actually 100% FSA. I also designed a cone fairing to fit behind the big outrunner. I bench tested this and with the full outlet ducting fitted thrust was increased by 5g compered to unducted.. so the fairing is working.

The installation is designed to be able to take either the AEO fan, GWS based fans, or the KP 32mm. for the KP fan the 26mm outlet represents 80% FSA which is perhaps smaller than ideal but i wanted to keep the ducting size constant so it's a compromise.

Inlet and outlet sizes are scale size, i did not have to 'cheat' at all. the only devaition from scale outline is a slight increase in tail area. The real Mig-17's tail is tiny.

The timer unit does allow 'throttling' so my comment about being overpowered was a bit tonge in cheek. The plan is to start trimming on low power and build up until things get 'exciting'. I'd much rather have a bit of power in reserve than be underpowered. Scale jets dont look right struggling about on the verge of a stall.


Fred,
Thanks for the data on R/C gear. I've done plenty of R/C in my time but no micro R/C so I'm not really up to speed on whart products are out there. It looks like it would be a reasonably straightforward conversion, weight would not be an issue anyway. Wing area is 498 sq cm (77 sq in).. Hopefully this will make it a 'floater' at 85g flying weight.. Freeflight models really need to be quite floaty otherwise survival prospects are not good.

I'll try to get the vertical stabiliser built tonight, perhaps the horizontal stab too if I get enough time.

Steve
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Last edited by JetPlaneFlyer; Feb 03, 2010 at 01:52 AM.
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Old Feb 03, 2010, 02:54 AM
Team30 Micro EDF
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Adelaide, Australia
Joined Apr 2004
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Steve, do you have more details on the cone fairing please? That's my next area I want to experiment in.
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