Genes scratch built glider speedster 40 inch ws - RC Groups
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Jul 02, 2010, 08:57 PM
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meanbaby's Avatar
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Genes scratch built glider speedster 40 inch ws


hi everyone

club buddie built a small glider speedster i though i wanted to share with you guys

plane made out of 3 mm depron with a symetrical wing covered with monocote, fuselage also made from 3mm depron and spackled and then thin CA soaked,

i gotta ask him the spec on the motor and esc but i know its the Scorpion eletronics and 4 inch cam props

he used 4 of those flat servos
http://www.hobbycity.com/hobbycity/s...tra-Thin_Servo

2 of them is burried in the back pf the fuselage for ele and rudder

total wingspan is 40 inch
he is not sure of AUW but i see him use 1300mah 3 cell 30c turnigy's

i will forward this thread to him so in hopes to get more info for you all if interested

enjoy
-pete
Gene d10 (3 min 9 sec)
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Sep 24, 2010, 02:07 AM
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fgene's Avatar
Ok, there seems to be more interest in this plane since I demonstrated it at NEAT FAIR 2010, so here are the most current specs:

Motor: Moxie Brushless Motor 3700KV For 450 Helicopter
http://www.lowpricerc.com/product_in...oducts_id=1047

I wrote a short review at the bottom of the page. I can't praise this motor highly enough. I think it's really unbeatable for the price.

Prop: Graupner 5.5x4.3 CAM speed

A bit overkill, I wish could find something like 5x4. Graupner don't make 5x4, unfortunately. APCs are inferior to Graupner at high RPMs, according to my experience.

ESC: Turnigy Plush 60a w/SBEC
http://www.hobbycity.com/hobbycity/s...eed_Controller

Very robust and trouble-free ESC. Handles 80A nicely, at least for a short time.

Battery: Rhino 1550 mah 3s 30C
http://www.hobbycity.com/hobbycity/s...idProduct=9326

Marvelous batteries. Can really work ABOVE the specified 30C rating. I have 4 of them since July. Sometimes they are very hot after WOT flying, but none of them has puffed yet and all the cells are still in balance.

Servos: VG 8.0g / 1.5kg / .14sec Ultra-Thin
http://www.hobbycity.com/hobbycity/s...idProduct=7026

D-10 has 4 of them. These are the only servos I was able to fit inside the fuselage which are powerful enough. The critical cogs of the gear train are metal. Unfortunately they are not as precise as I would like them to be, and there is a small freeplay at the main shaft (similar to most metal gear servos). Still, they are adequate.

Gyros: http://www.hobbycity.com/hobbycity/s...nel_Controlled

One for each aeleron. Really helpful at landings with spoilerons deployed, in regular flight the gyro gain could be set at minimum.

Receiver: AR6110

This plane should probably be equipped with a full range RX, but there is just no space for it to fit into. I never had a single glitch with 6110 no matter how high or how far the plane was, I hope I will never have. Just in case, the failsafe is programmed so that the plane will deploy flaperons to kill speed, if the radio contact is lost.


My goal was to see if it's possible to built a very high speed plane from materials that to not require any sophisticated techniques to work with, like foam. I think I succeded for the most part My previous two attempts failed because
a) the leading edge wasn't straight enough, which caused the plane to roll uncontrollably at high speed;
b) the wing wasn't strong enough to withstand the air pressure while maneuvering at high speed (it snapped in midflight).

So I knew the wing was the most critical part, and it took me a lot of time to design the one that works. Now the wing is made of two pieces of 2mm depron, folded together around the spar, glued with Gorilla and covered with monokote film on the outside. It has a semi-symmetrical profile, because the bottom foam sheet was a little bit narrower than the top one. The spar is a combination of hard wood, steel, carbon and J-B Weld epoxy. The leading edge is reinforced with carbon rod, which also helps to keep it straight. The wing tips are made of balsa.

What else to say? With current power system, D-10 accelerates like "a bat out of hell" as some RC fellows put it, and reaches speeds upwards of 100mph in no time. The maximum speed it's been clocked at is 128 mph, but that was BEFORE I upgraded the motor and ESC. So I estimate the current max. speed is about 140 mph, conservatively. I can't really tell myself, but I've heard comments from other folks at NEAT Fair that its speed was about the same as in factory-built, fiberglass pylon racers we also saw there flying (and crashing, unfortunately ).

Additionally, D-10 can fly very slow without going into a stall because the wing tip shape allows it, and also because it's quite light: only 512 grams without battery. That's much less weight than in most pylon racers of similar size. I also like the fact that it's capable of taxiing on asphalt and has a functional rudder, unlike most pylon racers.

There's another video of it on youtube:
D-10 128 mph RC airplane (5 min 22 sec)


Since this video was taken, I have upgraded the motor and ESC so it became about 1.7 times more powerful. The description is still mostly accurate.

I'll be happy to answer any specific question.
Sep 24, 2010, 08:48 AM
Lawn Dart Specialist
SixDeuces's Avatar
Thank you for sharing this information. I'd defnitely be interested in knowing more about the airframe construction.
Sep 24, 2010, 11:21 AM
Registered User
fgene's Avatar
Quote:
Originally Posted by SixDeuces
Thank you for sharing this information. I'd defnitely be interested in knowing more about the airframe construction.
I'll be posting some photos and drawings later today.
Sep 24, 2010, 12:55 PM
Lawn Dart Specialist
SixDeuces's Avatar
I was very impressed with its performance at NEAT, and very surprised by the relatively inexpensive equipment used. This is definitely a case of "mind over money". I'm very tempted to try duplicating your effort.
Sep 24, 2010, 03:25 PM
Registered User
fgene's Avatar
Quote:
Originally Posted by SixDeuces
I was very impressed with its performance at NEAT, and very surprised by the relatively inexpensive equipment used. This is definitely a case of "mind over money". I'm very tempted to try duplicating your effort.
Thanks, I am very glad to hear that This thread was here for several months and no one seemed to be interested in D-10 at all. Myself, I am quite proud of this plane, because i know from experience how hard is it to build an airworthy frame that can withstand such speeds, from cheap materials and without any sophisticated measurement tools.
Sep 24, 2010, 05:04 PM
Registered User
Nice work, that's one sweet little plane
Sep 25, 2010, 07:58 AM
Here comes the rooster...
JesseB's Avatar
Nice work Gene!
Sep 26, 2010, 01:37 AM
Registered User
fgene's Avatar
Thanks guys!

There's one little thing I forgot to mention. People have asked me why there're Scorpion stickers on the plane if there are no Scorpion parts inside. Well, there were parts made by Scorpion, namely HK-2221-10 motor and Commander 45A ESC. The former didn't provide enough RPM for my favorite props. Nothing's wrong with the motor, it was my mistake choosing the -10 variety. I should have bought an -8 or even -6. A thought of re-winding an otherwise perfectly good motor still scares me. So, when I replaced the motor, the ESC had to be replaced too, because being only 45A it couldn't safely handle the increased amperage draw. The stickers still remain because they provide me with visual clues about plane's attitude, and I am kinda used to rely on them while flying. Removing them would make the plane a little bit more unsafe for me, so the stickers are going to stick Oh and by the way, despite its small size, D-10 could be extremely dangerous if mishandled, in the air or on the ground, just like any other speed model with a high-RPM front mounted prop.

I sincerely hope that Lucien Miller, who I beleive is an incredibly nice person, will not take this clarification as an insult to the brand he represents
Last edited by fgene; Sep 26, 2010 at 02:00 AM.
Sep 26, 2010, 07:56 PM
Hooper, full throttle!
Tommy D's Avatar
Thanks for all the info from the model. Watching it fly at NEAT 2010 was a lot of fun. Didn't you have something very similar to it at NEAT 09?

+1 for MOXIE brand motors. I have a 37mm one in my Night Flying Fun Cub and it's well worth the 16 or so dollars it cost me!

Tommy D
Sep 26, 2010, 09:42 PM
Registered User
fgene's Avatar
Quote:
Originally Posted by Tommy D
Thanks for all the info from the model. Watching it fly at NEAT 2010 was a lot of fun. Didn't you have something very similar to it at NEAT 09?
Must be someone else... This was my first year at NEAT, and D-10 is my first high speed plane that can actually do what it's built for

RIP, D-8 and D-10 incarnation #1.
Sep 26, 2010, 11:34 PM
RA-TA-MA-HAT-TA
munce31's Avatar
That is one sweet plane man!
Sep 27, 2010, 08:50 AM
Lawn Dart Specialist
SixDeuces's Avatar
Gene,

How was the fuse constructed? Was the depron rolled to shape (heated?), or laminated and carved?
Sep 27, 2010, 03:45 PM
Registered User
fgene's Avatar
Quote:
Originally Posted by SixDeuces
Gene,

How was the fuse constructed? Was the depron rolled to shape (heated?), or laminated and carved?
This is what I did:

1) Attached seven 6-mm depron pieces to each other usen a double-sided Scotch tape
2) Sanded the resulting brick down, until it took the approximate shape of the fuselage
3) Took the depron pieces apart, removed the tape
4) With a small rounded file, made grooves in sheets #2 and #6 until I could put 2mm carbon rods into them
5) Glued pieces #2, #3, #4, #5, #6 and carbon rods together with Gorilla glue. Pieces #1 and #7 (bottom and top respectively) were put aside for now
6) Using hobby knife, made all necessary accomodations for electronics, wing support, mechanical links etc.
7) Installed and tested everything that could be installed and tested at this point, including tail, landing gear and engine firewall
8) Glued on depron pieces #1 and #7. A portion of #7 made a battery compartment door
9) Sanded the fuselage again until its shape was completed
10) Using a sharpened piece of telescopic antenna, drilled ventilation holes where they were needed
11) Covered the fuselage with epoxy, waited until dry and sanded again to perfection
12) Painted with acrylic paint, using a regular brush.
Last edited by fgene; Sep 27, 2010 at 04:37 PM. Reason: clarification


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