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Sep 08, 2009, 05:31 PM
D'oh.. Dumb Left Thumb
dekan's Avatar
IMO Pyromania may be a bit too popular as a hobby in Canada and America nowadays
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Sep 08, 2009, 09:24 PM
Curiouser and curiouser
Kokopeli's Avatar
Only because we have more trees left than you do LOL
Maybe our pyromania is equal to your football hooliganism, eh? - just outlets that would be better directed to building foamies.
(where did i put my matches - I hate it when I lose them)
If you want to take this nonsense one step further, you could consider our propensity for fully automatic assault weapons. (that is probably only in the states - not Canada) Whoops I better put a whole bunch of similes in here before someone gets the wrong idea

Better go to bed now - getting punchie.
Last edited by Kokopeli; Sep 09, 2009 at 09:18 PM.
Sep 09, 2009, 03:42 PM
Registered User

Mini Dren

I have to admit, I have the Drenalyn bug

Even though my attempt at a small light version (See above) resulted in a gorrila...although it turned out to be my most favorite foamie to date (out of about 20 previous builds)....I still wanted to see how small I could make one with conventional components....

here it is....virtually 100% 3mm Depron with no glue thruout
just two main cut pieces of foam

13" WS
14" Length
Three pieces: Wing, Fuselage/Fin, Motor Mount block
10g HXT motor
5g servos
2S360mah battery (15min flights)

AUW 2.9oz
2.55 oz/sqft (could be lower with smaller battery )

Nose Block is scrap EPP with 3mm Depron sides....1/16" ply firewall....

Slot the block and hot glue to fuselage flush with wing for 5deg down thrust
Note that the camber is simply done with straight lines on the fuselage..

Note also that the single piece fuselage slides into the slot in the rear of the wing...I glue the forward section of the wing first,then work back to the end, slipping the rear fuse/fin into the wing slot as you go...

This version flies just like my 20" one (without rudder of course)....floaty...but great inverted and good wind penetration and speed those Drenalyns!

WARNING....this is not a gorilla was done to see how light I could get it for the 10g motor...its not ultra delicate (I have face planted it several times without injury) but it WILL break on any hard impact...soo...just don't crash hard took me 4 hours from start to maiden, so rebuilds wouldn't be a big deal...enjoy

PS: the CG shown on the plans is about may want to start with 25%( ie move batt forward some) unless you have experience with 3D planes balanced to neutral stability...note in the underside picture below, you see I have the batt forward of the the CG line in that was windy the last flight and I wanted to calm it down some...that moved the CG forward about 1/8" from the line..
Last edited by Atx_Heli; Sep 09, 2009 at 04:10 PM.
Sep 09, 2009, 04:09 PM
a little kid at heart
poulsbobill's Avatar
Any chance of a vid on the little guy?


Sep 09, 2009, 06:00 PM
flyin' fool
goldguy's Avatar

Now you know why the Drenalyn is my all time favorite low aspect ratio foamy....waaaay better then just flat. Push it to the limits and it never lets you down.

I built a sub 4 oz. 14 incher from 3mm Depron a few years back for indoor and it flew great. A FB talked me out of it, stuck on some big electronics and promptly bashed it to bits. I sez to him ......"heavy means fast", but he didn't listen. So he went with an EPP 17" and all was well.

To beef up the LE when using thin Depron, I got some vinyl sign material, cut a 1/2 strip and installed it by pulling tight and wrapping it around both below and above in front of my shop electric heater. Worked like a charm and helped keep things in one big piece. I found some stretchy celo tape at the local hardware store that works well too, much lighter then the vinyl.

I like your EPP 'nose extension motor mount automatic balancer' idea.

Think I'll all go whip out a Depron 13 incher to give some of my tiny gear a home.

Later: Frank
Last edited by goldguy; Sep 09, 2009 at 06:06 PM.
Sep 09, 2009, 06:46 PM
flyin' fool
goldguy's Avatar
To clean up the wiring................

Make a foam 'hole' drill by taking a length of 1/4 brass or aluminum tubing and sharpen the end from the inside with a #11 Exacto blade or small round file, then hit it in a few places with a small triangular file to give the end some teeth.

You can poke and weave the excess wire into the holes for a nice neat installation for less drag. Check post #15.
Sep 09, 2009, 08:19 PM
Curiouser and curiouser
Kokopeli's Avatar
Okay: if I build the Drenalyn out of FFF, how big do you think I should make it to compensate for the heavier foam? Seems like the larger area (size squared) vs. the lack of increasing the volume (size cubed) of the foam, for a bigger plane would allow me to find a larger size that would perform as good as your drenalyns built out of that light stuff that I don't have. I have over a half bundle of FFF left. Of course I will have to put a larger motor (and battery and ESC, and ...) on it, eh?
Maybe I could build the 'fuse in the taco form that Glen likes, using my gpw foam bender.

Sep 10, 2009, 01:31 AM
flyin' fool
goldguy's Avatar
My latest is a 19 x 20.5 incher from FFF at 10 oz and a loading of 4.0 oz. sft. Porky, but, boy oh boy, does it perform. Komodo power on 3S for instant thrust, that equals pure sinful joy. I went from a 2S setup at 7.9 oz/3.2 sft just because, or maybe it's just because I like to be bad. The lighter version was heavenly, the heavier more devilish .

No need to fiddle around bending foam, just glue it to the top of the airfoil shaped fuse starting at the front using hot melt and work you way to the TE in short stages. You can do the whole process while holding it in your hands keeping the pressure on while the glue cools. The bend in the foam adds tremendous strength and having it under tension keep everything straight. No need to make a simple thing complicated.

Run the ripple span wise when using FFF and for Depron, keep in mind it has a in it bends one way better then the other.

Changed my mind on the 13 and went with a 14, shooting for 3.5 ounces for a hallway flyer.
Sep 10, 2009, 02:10 PM
Registered User
Originally Posted by poulsbobill
Any chance of a vid on the little guy?


here is some...its my first attempt, so its sometimes misframed...

Drenalyn RC plane (4 min 34 sec)

I have found on the 13"er that since the battery accounts for a significant portion of the total weight, placing the battery on the fuse side is not will notice in the video a lot of right turns....because the battery is mounted on the right side, right turns are more natural, smooth and easy....after I shot the video, I moved the battery to the top of the wing and this small movement to the centerline made turns equally easy and rolls much more smooth and wouldn't think that 1/8" movement of the position of the battery's center would make such a big difference, but lateral balance is very important on these very light craft...
Last edited by Atx_Heli; Sep 10, 2009 at 02:27 PM.
Sep 10, 2009, 03:15 PM
a little kid at heart
poulsbobill's Avatar
Nice. Thank you!!

Sep 10, 2009, 03:46 PM
flyin' fool
goldguy's Avatar
Just finished my 14 incher and it weighed in at 3.59 oz. RTF for a loading of 2.74........ powered by a Turnigy C1822 spinning a 6X3 on 2S 350s, Turnigy 6A ESC, CC Berg 4 ch RX and two 3.7 servos.

Off to the maiden and fine tune...............hope it flies as well as you 13.
Sep 10, 2009, 07:02 PM
Registered User
Just curious, why are you dropping the rudder servo? Isn't this just a more floaty SD (more LE) without it?
Sep 10, 2009, 08:29 PM
Registered User
Originally Posted by tymbrewolf
Just curious, why are you dropping the rudder servo? Isn't this just a more floaty SD (more LE) without it?
in my opinion, its a lot more stable and infinitely better inverted than an SD...I've had both 24" and 16" versions of the SD and its a great plane due to its the Nutball...but I definitely prefer the Drenalyn...

the Drenalyn IS a lot easier to control with rudder when low and slow, but in the tiny ones, floaty is more fun IMHO....and it is still possible to have fun low and slow as you see the video above without the rudder....where the wing loading can take it, I would always have a rudder...
Sep 11, 2009, 05:01 AM
flyin' fool
goldguy's Avatar
Maidened sans rudder and hand launch handle/canopy cuz I ran out of time. Gets dark early now, so we bumped up evening flying to 5PM. Anyhoo...........what a blast, floaty or fast, flies great, just like all Drenalyns.
Sep 11, 2009, 09:59 AM
flyin' fool
goldguy's Avatar
The Simple Delta and the Drenalyn are two completely different flying machines for two completely different flying styles.

As concern rudder, I've found that getting the proper height takes a bit of fine tuning. ...not too tall, not too short, but just right. With just a vert. stab it's not a problem.

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