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Aug 08, 2006, 10:55 AM
Retired CAD guy
birdofplay's Avatar

New design Low Aspect, Tunnel, Rogollo combo

I've been meaning to share this design in the Groups for some time.
A few guys in the Harpy thread have been pointed to my URL
but now I thought I'd just go ahead and make it public.

It's a follow-on from a paperplane design
Many many years ago, I have no idea how, I started building this design
It was different from other "typical" Paper airplanes.
It didnt go fast as a dart and it FLOATED a long way without much
of a toss. Design date was as far back as the 70's at least.
It's kind of Rogollo like and Tunnel Hull like .
I couldnt find anything like it in any of my paper airplane book collections,

so here goes ...

To illustrate the concept and derivation of this project
Lets make a familiar but unique Paper Airplane first.
Follow this series of photos and have some fun
Just read the directions IN THE PIX and make one for yourself.
Last edited by birdofplay; Aug 08, 2006 at 11:42 AM.
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Aug 08, 2006, 10:57 AM
Retired CAD guy
birdofplay's Avatar
OK 2 minutes are UP, you should be done now !!!

At this point you should have a model to work with.
Very little "up" is needed, if any, to get it to glide well
Make any adjustments slowly and gently.
It'll glide across the room when trimmed properly.

Now here is where the fun starts !
I attempted to MODEL this design in 3D CAD.
Those long and wierd curved surfaces gave me FITS !!!
Regardless, I managed to get these renderings from my efforts
plus a few conclusions and tentative dimensions to get me started.

After a few test glides with the Depron version I realized that this design
was going to need a Verticle Stab - either on Topside or Underneath.
Last edited by birdofplay; Aug 08, 2006 at 11:02 AM.
Aug 08, 2006, 11:08 AM
You sabotaged my plane.
eliworm's Avatar
I remember that design. Some toy company also made their copy of it as well. I do remember them gliding very well. I had mine in the late 70s. Hmmmmm, need to go steal some of the wifes printer paper.
Aug 08, 2006, 11:09 AM
Retired CAD guy
birdofplay's Avatar
Now the challenge of bending up a Depron version.
Follow the picture narrative along as I SCREW IT UP !

The Pix should be IN ORDER and since I did this write up
on MY web site a while back the notes were placed ON THE PIX
Aug 08, 2006, 11:19 AM
Retired CAD guy
birdofplay's Avatar
Next came Radio and Motor installation.

Getting Lazy and excited I decided, as an expedient , to
simply put the motor up front. It made balancing so much easier
Plus shorter connections made things lighter overall

I mounted the servos in cutouts in the centerline crutch.
Simple Goldenrod connections from servo to the Taped Hinge Elevons.
I DID NOT SKIN in the back sections of the wing as shown
in the CAD renderings, at least NOT YET.

By August 3, 2006 and I'd finally managed to finish this project

Here is a shot of the completed plane sitting on a scale
What you cant see in the pix is that the AUW is only 8.1 Oz
Thats my stock wind Komodo 273 v2 up front
I should have used my newer and lighter K257, but it's mounted on my Mach-3
Speed is NOT a goal so motor size can be small with a torquey kinda low rpm

I've placed some 3M velcro on the central spine to hold the battery.
I'm using a 700ma 3s1p Lipo from Commonsenserc
The servos are simply inserted into holes cut into the spine and HOT melt glued for security

I choose a light, shorter range GWS Rx and a lightweight antenna and taped them inside
OK , all my Bergs are currently in use so the GWS was a fall back

Some Goldenrod was laying around so it's used for the fairly straight connection to the elevons
I hotmelted the Golden rod as necessary to achieve surface "zero" centering
The "horns" are a thin plastic hinge with the pin removed and Hotmelted into
slots cut into the elevons. The hinge edge kinda "detented" into the center of the foam

Maiden flight was at the Electric meet in Lacey WA last weekend Aug 6-7, 2006.

A Maiden Flight Video is currently at
NOTE it's about 6-7 megs ! ! !
Last edited by birdofplay; Aug 08, 2006 at 12:11 PM.
Aug 08, 2006, 11:27 AM
Retired CAD guy
birdofplay's Avatar
Balance was pretty close to that of the Paper version.
Handling was ... well ... not authoritive.
But it was so stable it didnt seem to matter.
Aug 08, 2006, 11:34 AM
Retired CAD guy
birdofplay's Avatar
Following the Lacey Maiden flights I decided, ON SUGGESTIONS received
at that meet from several interested fellas,

to increase the ELEVON size by about 2X. and increase the throws too.

Several suggestions were offered at the meet but I figure to tackle them One At A Time !

Here's a few ...
Tapered Elevons - wider at the tips for more control.
Internal Ducted Fans for power - a natural in this structure
Landing gear - I kinda had this in mind already - see CAD pix.
Swap rudder to under side - again see CAD study.
Mid engine or central "Thru -body" prop location.

BTW a rear prop location is OFF my list as I'm really tired of having to
TOSS models without the motor running.

Regardless ...
Yesterday, In winds that would keep most planes on the ground I Tossed off the lastest mod
and was pleased at the increased response. I felt much more "in control"
and didnt have to nurse the model around at all.
Full throttle yeilds VERTICLE climbs. But with all the wind I cant actually judge the glide as compared to the original paper version.
As a powered model it's great. As a glider its a bit dissappointing as compared to the original paper expectations. But it still has some unusual flying characteristics that make it a a fun ship to add to your collection.

Bigger elevons are a must !

I do intend to REMOVE that LARGE RUDDER next !
I seems to make it TOO stable IMHO.

Regardless the NEXT in this series of experiments will be reported here

Thanks for listening and Enjoy your own versions :-)
Last edited by birdofplay; Aug 08, 2006 at 02:51 PM.
Aug 08, 2006, 11:51 AM
Retired CAD guy
birdofplay's Avatar
eliworm: Yeah I need some assist in determining the origin of the paper design.

I have a guy in Ohio who claims to have a similar design from the 50 or 60's
that was used in a Wright-Pat contest. Thanks to Synthfilker of Ohio

Then another guy noted a similarity to this design in a Stepped Airfoil pattent
from some guys named Klein - Fogleman - Thanks to Larry of GIG harbor
Last edited by birdofplay; Aug 08, 2006 at 12:10 PM.
Aug 08, 2006, 02:56 PM
Retired CAD guy
birdofplay's Avatar
Well I just returned from calm wind flying at a nearby schoolyard.

It's lots better with the big surfaces and it glides Not Too Bad IMHO.

I was doing a bunch of loops and Somehow one of my 3.5mm connectors
manged to come LOOSE ! ! ! no motor - oh oh !!! no radio at all !
Fortunately the plane self righted and pointed itself towards
the larger part of the field and it just settled in for a nice landing.
Wheeeew ! ! !

I will secure the connectors with some tape next time out.
Aug 08, 2006, 07:18 PM
Permanently Banned
Larry3215's Avatar
On the day you start this thread - they split off "DIY Foamies" into a new seperate forum.

As of today - this is the "Kit Foamies" forum.

So - when will kits be available??

Aug 08, 2006, 07:22 PM
Permanently Banned
Larry3215's Avatar
I would recomend you keep the rudder - but make it functional.

I find that with these square to less than 1/1 aspect ratio designs, that they are much easier to controll at low speeds if you stear with rudder. This is especially true in harrier mode. You can fly around using only the left stick - throttle becomes altitude controll and rudder to stear

Aug 08, 2006, 07:28 PM
Retired CAD guy
birdofplay's Avatar
Kits ???

Start with two sheets of 3mm depron and follow the directions herein !

I spoz I "could" sell ya some depron :-)

OK BEFORE I remove the Verticle stab
I will articulate it and give that Rudder Idea a try.

BTW will "Bit" kits be available soon ? :-)
Aug 08, 2006, 07:36 PM
Permanently Banned
Larry3215's Avatar
Originally Posted by birdofplay
Kits ???

Start with two sheets of 3mm depron and follow the directions herein !

I spoz I "could" sell ya some depron :-)

OK BEFORE I remove the Verticle stab
I will articulate it and give that Rudder Idea a try.

BTW will "Bit" kits be available soon ? :-)
They go on the martket today. Just send me $999.99 plus shipping and a kit will be on your door soon

Aug 08, 2006, 07:55 PM
Retired CAD guy
birdofplay's Avatar
Yeah, yeah Thats IT !!!!

The Check's IN The Mail, fer sure

Send kit NOW - Trust Me
Aug 08, 2006, 08:24 PM
Registered User
ewo's Avatar


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