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Oct 28, 2005, 05:28 AM
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The Estratos..Plans here for an easy cheap Depron Delta ..

EDIT...NEW PLANS ADDED and a construction sugestion

Going through some old mags I came across what must be one of the earliest of foamies. The Stratos design that was produced by a world champ Hanno Prettner. for a 40 size tuned pipe motor and had great performance. It was made from 1" flat polystyrene foam with some balsa edges

The shape and layout appealed and so the Estratos was born

The 595mm Estratos is made from 3mm Depron. AUW is arround 6.5 oz depending on battery. I used a home made cdrom motor.. 7x3.5 prop .. 11.1v lipo 700mA .. two 4.5g servos .. 10A esc ..
Elevator 3/4" up down at widest point
Ailerons 1/2" up down at widest point

Construction of the 595 used one sheet of foam 595x420 with some left over. The design is so simple that full size plans are not needed, just some measuring.

First flights should be made with the C.O.G. at the indicated forward point, .. Also the control deflections are ample so have some lower settings on your down rates
I maidened it yesterday, without any crashes
It flew well, had vertical performance. Only problem I had was the high wind bouncing it about.

To improve performance in windy conditions there is also a 750mm span version, Construction is the same but use a thicker grade of depron.
The 750 is my favorite. Dont worry about adding weight mine flies great at 12+ oz. The top has been fully covered with packing tape strips in a flag design
MY flying setup is
Elevator +- 3/4"
Ailerons +- 1 1/2"
Rudders as much as posible.
Cheap bell 2408-21 motor and esc combo, 11.1v 1000Ma lipo, 8x4 prop.
The 750 version has become my hack of choice,

3mm depron for the 595 ...5-6mm depron for the 750
3mm carbon fibre tube
2" bright coloured packing tape ( from Staples office supplies in the uk)
Glue used UHU por or epoxy
Velcro hook and loop tape

1.. Cut the foam
2.. Tape a 3mm carbon tube to the leading edge of the main wing section with 2" clear tape, mine was joined at the centre with a bit of wire bent to the correct angle
3.. Tape the front wing sections in place with the rear sections. I used 2" bright coloured packing tape top and bottom, using different colours, 1/2" overlap over the carbon fibre tube
4..Champher the rear edge of the wing and the front edges of the elevons
5.. Using more 2" coloured packing tape top and bottom, fix your elevons in place. make sure they move freely
6.. Fix some 1/4" triagle balsa to the fusulage sides. make up mirrored
7.. fix fuse sides to the wing

Thats the main build. Now fit your motor, controls and electrics how you want.

EDIT These days I would do a slightly different build, using the KFm2 or KFm4 section..If you do this forget the CF spar and use balsa spars under the extra layer of depron with tape over..
heres an example build thread... and I think the Plank here (the Nifty) is a much better flyer even if it doesnt look so pretty..

I put my servos at the back, in a depron servo tray glued across the fuse, the battery is just in front, the rec and esc were fixed on the fuse sides.
I used velcro to hold the battery, esc and rec in place. The servos were glued in place with a low melt gun. The low melt is not hard to pull off from the servos, but gives a firm hold

8. I put a couple of small balsa plates across the top of the fuse,at the front and rear, for additional strength. Made a top depron hatch hinged at the front with more coloured 2" tape

Thats it. Not difficult to make.. Flies well. Just remember to have lower rate settings available. Because as it is setup, it is responsive
Last edited by davereap; Nov 07, 2015 at 01:55 AM.
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Oct 28, 2005, 05:38 AM
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Estratos for Reflex XTR

I have sent a model of the Estratos to the website It is available now for downloading to use on the Reflex XTR simulator for those wishing to fly indoors
Last edited by davereap; Nov 03, 2005 at 05:43 PM.
Oct 28, 2005, 07:29 AM
“There’s no place like Foam”
gpw's Avatar
Dave ... really pretty COOL!!!! Thanks for the plans !!!!
Latest blog entry: Lost plans
Nov 01, 2005, 07:45 AM
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750mm span

Due to the nice flying characteristics a larger 750mm span version has now been made. AUW 10-12oz .. Axi2208/34 .. 8x4" prop .. 11.1v lipo. This should be less troubled by windy conditions. Scale up by a factor of x1.25
Built using 6mm depron, I used a single 3mm carbon tube as a wing reinforcement. It would be stiffer with a 5mm carbon flat spar, but I was in too much of a rush to get the bigger version made.

The 3mm tube proved ok flexing noticed
Last edited by davereap; Nov 12, 2005 at 03:06 AM.
Nov 01, 2005, 08:20 AM
“There’s no place like Foam”
gpw's Avatar
Love the "Austin Powers " colour scheme.....hahahahahaha Sorry ,
Latest blog entry: Lost plans
Nov 02, 2005, 07:32 AM
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Just flying the flag..... Get some more flags up
Nov 02, 2005, 02:21 PM
Robots... robots everywhere
minifly's Avatar
looks nice

from what i can see, it will be balanced in both roll and pitch, something that is difficult with wings. deltas roll too much, and planks are too pitch sensitive.

this should be a nice compromise.
great find...
Nov 03, 2005, 06:00 PM
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davereap's Avatar
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The estratos is not at all pitch sensitive when given a slightly forward centre of gravity. You can roll as fast as you like, depending on your aileron movement. It is quite stable with hands off, but it is no trainer.

good flying to you all....
Nov 03, 2005, 07:03 PM
"Hobby Apparatus" Flyer
Mikey C.'s Avatar
good looking plane! I might have to try this...
Nov 06, 2005, 05:30 AM
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Flag maidened

Maidened the flag colour scheme yesterday... total failure ...rolled to right and crashed.. now undergoing repairs... Be aware this plane does not fly when the ailerons are going the wrong ******* way. What a stupid mistake to make. I even looked at them and thought they were correct.. .. I then took the 595 version out. With the ailerons going the correct way it is flying really well. The home made cdrom motor is very quiet and has plenty of power. The COG as per the plan is good. now that I am getting used to it I am increasing the control throws. Took it up high and glided down, quite a reasonable glide, plenty of control.
Last edited by davereap; Nov 06, 2005 at 05:45 AM.
Nov 06, 2005, 05:33 AM
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more pics

here are a couple of extra pics of interest. the yellow 40 powered version is from 1984 It flew a treat but was retired when a control horn came away. The other pic which gives an idea of the difference in size between the 595 and the 750, shows most of the parts that are needed
Last edited by davereap; Nov 06, 2005 at 05:50 AM.
Nov 06, 2005, 08:28 AM
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LLoo's Avatar
Dave that's too bad about the crash. The excitement of a maiden flight causes blindness! I've done it myself....if the truth be told more than once.

I'm a big fan of simple designs. The Estratos looks like it could be built in a couple of evenings.

Would you mind if I put a copy of your plans/pictures on the EFlight Wiki site?

Nov 06, 2005, 09:55 AM
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davereap's Avatar
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I am happy for anyone to use this design. just post your results and pictures here.
Anyone with reflex xtr can download the estratos for their sim. The download from also contains plans for the design.
You should be able to knock one up in one evening they are that easy!

Most of my building time is spent stripping the paper off the foam board I use, or doing the colour scheme. Cut from depron taped and superglued together, it will take longer to fit the radio bits than to build the model
Last edited by davereap; Nov 07, 2005 at 02:10 AM.
Nov 06, 2005, 11:23 AM
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aV8ter's Avatar
How about putting a single wheel in front and two skids in the back for landing gear? Like the I.F.O.

Nov 08, 2005, 07:25 AM
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davereap's Avatar
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As all my flying is done off grass, wheels dont help, it hand launches easy, grab the top of the fusulage and give an gentle underarm throw, away it goes.. can be slowed to nearly nothing for landing. Might be worth a go for trying indoor flight. give you both thumbs ready on the controls from the start. Make the front longer than the rear to give a good angle of attack for take off. Might be worth making a carbon fibre dolly that can be put on when wanted..
Think I will try that

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