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-   -   "Open" design (http://www.rcuniverse.com/forum/electric-general-discussion-106/402976-open-design.html)

a088008 12-06-2002 09:30 PM

"Open" design
 
I'm an r/c aircraft designer and builder.

I would be very interested to know if anyone has an interest in participating in the designing and building of an electric plane.
I'm interested in a plane for "general" consumption and novice to moderate building skill (nothing too fancy).

A restriction I would like to propose is that anyone should be able to build the plane from balsa and ply, so that all of the particilpants can easily build the final design. Then we can all show off our individual creations and swop stories and ideas on how to improve the design.

The other restriction I would like to propose is that the plane be big enought to accomodate standard size radio equipement, but you can fly the plane with smaller equipement if you wish.

What do you think? Interested? If you are, let's use this forum thread to get started with some suggestions on plane characteristics. We'll get to design tools later.

P.S. The "Open" design means that participation should be open to anyone and that the plans must always be free. If a kit manufacturer wishes to produce the plane they are welcome to, but the FULL plans must always be included in the kit and not be included in the price of the kit. Also, all participants must always be mentioned on the plans.

-Q.

cabanestrut2002 12-08-2002 12:19 AM

"Open" design
 
For a start, what type of aircraft are we talking about; aerobatic,power glider, trainer etc?

a088008 12-08-2002 07:30 AM

Anything is a possibility
 
I would like to hear any ideas. Anything goes.
Maybe we could come to some agreement on something that all of the participants (designers) are interested in.

We could go for aerobatic, glider, trainer, scale, warbird. Whatever captures your interest and you would think would be worthwhile. Also, something you are prepared to build.

I would like to suggest maybe doing something that is unique, or has not been done before.

Maybe a 4 motor WWII bomber that has a 100" wingspan. Only kidding - maybe. ;)
-Q.

RC_Eflyer-RCU 12-08-2002 08:28 AM

"Open" design
 
Using stuff like standard size servos and such would lead to fairly large stuff. Since you don't need such large servos on some of these electrics, you can actually get away with very small servos. I use HS-81's on my E3D, and thats more than enough. I don't think I'd use Standard servos on anything that was smaller than say 80 inches.

For example, even if I was flying a Diablotin Super I'd still only use Hitec HS 225's to save the weight.

basically what I'm saying is that the restriction of having to make it accomodate standard servos's isn't the greatest idea for an "open" design contest thing.

Aside from that I love the idea of a contest. Does anybody win any thing, or is this just a for fun contest.

My vote would be to make it a contest for a scale warbird or of scale homebuilt aircraft.

--Paul

a088008 12-08-2002 07:02 PM

It's ALL "open" to discussion
 
1 Attachment(s)
In a nutshell, my restrictions were only suggestions. I certainly do not want to restrict creativity.

The standard servos are only a suggestion, since it would allow gas modellers to participate (They generally have standard radio gear lying around.) I also prefer larger aeroplanes, since they tend to fly well and are smoother in the air, but it's only my preference. We need to come to a group agreement.

Info: I currently fly a 60" electric that I designed (I've attached a picture of it.) It has 4 standard servos and a standard receiver. I have the plane setup with flaperons with a servo in each wing. Yes, the plane does weight a bit more than it should, but the weight of the motor battery is far more than that of the radio gear.

I certainly would like the idea of designing a warbird, but not a Spitfire, Mustang, Corsair, Hellcat, etc. They have all been done before, and anyone can pick up a kit or ARF of one of them. I'd like to design something that you don't very often see in electric models.

I also like the idea of making an aerobatic model, but those are faily common. The idea of a home built aircraft is an excellent one! There are lots of aeroplanes that are perfect candidates. Here are some sites to look at:
http://www.lancair.com/
http://members.aol.com/erospace/index.html
http://www.pimaair.org/exp_qck.htm
Some Burt Rutan designs might also be nice.

I would like to clarify what this project is intended for. It will not be a contest unless there are 100's of people who are interested and would like the idea of splitting up into design teams and then form a contest. I would like to get to a point where we have a design that is a combination of the best that everyone in the team has to offer. A true meeting of minds. Some will be better at aerodynamic theory and other will know what flies well based on years of piloting experience. Others will know just the right way to build up the wing so that it is straight and true.

We could definitely setup a contest for the best looking plane built from the final design. Anyone know of a sponsor for prizes? Maybe you can speak to your local model shop and come up with some arrangement. ;)

Hope you guys are getting excited. I know I am. I can't wait to get started. Once we have decided on what to design we can discuss what CAD programs to use, and what aerodynamic software might be required.

-Q.

a088008 12-09-2002 12:32 AM

What's in a name?
 
Ok. How about a good name? Any suggestions. It would, however, help if we had an idea of what we were going to design and build.

Quote:

Originally posted by aeropal
Avoid naming the project "Pepper", to stay out of trouble if one should ever collide with a baseball field backstop. Many are posted with signs stating "No Pepper Against Backstop".

RC_Eflyer-RCU 12-10-2002 01:00 AM

"Open" design
 
Why don't we all set to work now, and in a couple of months, bring our designs to the table, no matter what they are (unless its a design of something that is so friggen common) I'd say that it should only be scale airplanes, no sport planes.

--Paul

a088008 12-10-2002 05:28 AM

Great subject!
 
The DeHavlin "Caribou" is a great subject! This is exactly the type of unique plane I had in mind.
Who else has suggestions, or should we go ahead and start with choosing the scale and specs for the plane?

-Q.

Quote:

Originally posted by aeropal
In a stand-way-off scale category, the DeHavlin "Caribou" would be a somewhat unique subject to consider. By taking a few liberties with the aircraft porportions, and very light (perhaps profile) construction using mini-servos, it might fly with twin 12 watt 280's through a 10 amp speed 400 motor controller.

a088008 12-10-2002 05:44 AM

Good idea
 
The initial idea for the"Open" design was to all contribute to a single design, but we can certainly consider many designs. I, in hind-sight, like your idea of many designs as this would give people a choice of building subjects. Some might prefer a single prop plane and others might prefer a choice of scales to build from. We could even make design teams that each work on one of the designs.

If we are going to start now then can I make the suggestion that we design each plane in a CAD program and exchange designs in the .DXF file format. I have found a free program that is much like AUTOCAD and has the capability to draw in 3D. Here is a webpage to download the evaluation version:
http://www.cadopia.com/products/download.asp

I think drawing a general scale skeleton of the plane would help us get started. We can then modify the relative dimensions to be more flight worthy. We're gonna need some aerodynamic theory to get them right. Who can help, or has a program that can give suggested surface areas for the wing, horizontal stabilizer. and vertical stabilizer?


Quote:

Originally posted by RC_Eflyer
Why don't we all set to work now, and in a couple of months, bring our designs to the table, no matter what they are (unless its a design of something that is so friggen common) I'd say that it should only be scale airplanes, no sport planes.

--Paul


a088008 12-10-2002 05:49 AM

Different Design Teams
 
Can I make a suggestion that if we are going to create more than one design that we create individual threads for each design team. We can then post the thread's name in this thread so that there is a common reference to all of them.

A standard naming convetion would be something like:
"Open" Design - DeHavlin "Caribou" - 1/10 Scale - Team "Propnuts"

-Q.

a088008 12-10-2002 06:16 AM

Scale Specs of the "Caribou"
 
Here are the 1:1 scale specs of the De Havilland Canada DHC-4A "Caribou":

(found at http://users.chariot.net.au/~theburfs/caribouMAIN.html)

De Havilland Canada DHC-4A Caribou
TYPE: STOL tactical transport
COUNTRY OF ORIGIN: Canada
ENGINES: 2x Pratt & Whitney R-2000 Twin Wasp piston engines, each of 1450 hp.
DIMENSIONS:
Wingspan: 95 ft 7.5 in / 29.15 m.
Length: 72 ft 7 in / 22.13 m.
Height: 31 ft 9 in / 9.68 m.
PERFORMANCE:
Max. speed: 188 kts / 348 kph
Normal cruise: 158 kts / 293 kph
Initial climb: 1,355 ft / 413 m. per min.
Service ceiling: 24,800 ft / 7,560 m.
Max. range: 1,135 n.m. / 2,100 km.
ACCOMMODATION: Flight crew of two.
32 troops, or 26 fully equipped paratroops.
WEIGHTS:
Empty weight: 18,260 lb / 8,283 kg
Max. loaded: 28,500 lb / 12,927 kg
CREW: 2

cabanestrut2002 12-10-2002 09:38 PM

"Open" design
 
are we all decided on the model as the Caribou
It looks like a very attractive aircraft that i have never seen modelled before.
It has good sized flying surfaces, a prime consideration for an electric model, especially if we are going to use standard gear.
What a huge fin! Very safe proportions to my eye.
I dont like the idea of scale profile models and they dont work out much lighter anyway.
Im thinking twin 400. Lots of people have this gear through models like the twinstar/twinjet/star jet etc.
This is beginning to look like an interestimg project!
Daniel Lee, Cornwall UK, www.rcflyers.fsnet.co.uk

RC_Eflyer-RCU 12-10-2002 09:58 PM

"Open" design
 
So we're going to form teams or are we all individuals. And can we design something, though equally cool? Such as a Vickers Wellington. :)

--Paul

a088008 12-10-2002 11:55 PM

400's are a good choice
 
Interesting indeed!

I like the idea of twin 400's. Many people have them and the speed controller will not need be excessively robust to handle the current drawn for both motors. Does anyone know how many continous amps can be expected to be drawn from two 400's? (ball-park figure, since the specs for 400's can differ by quite a bit)

I also like a "fat" fuesalage. A profile fuesalage would only detract from the plane's scale appearance.

Does anyone have a set of 3-view drawings of the DHC-4A, so we can get started with basics like the scale and the wing area?

-Q.

Quote:

Originally posted by cabanestrut2002
are we all decided on the model as the Caribou
It looks like a very attractive aircraft that i have never seen modelled before.
It has good sized flying surfaces, a prime consideration for an electric model, especially if we are going to use standard gear.
What a huge fin! Very safe proportions to my eye.
I dont like the idea of scale profile models and they dont work out much lighter anyway.
Im thinking twin 400. Lots of people have this gear through models like the twinstar/twinjet/star jet etc.
This is beginning to look like an interestimg project!
Daniel Lee, Cornwall UK, www.rcflyers.fsnet.co.uk


cabanestrut2002 12-10-2002 11:59 PM

"Open" design
 
no more than 35 amps at startup for a couple of soft speed 400's

ill see what i can find in the way of 3 views.
dan

a088008 12-11-2002 12:01 AM

2 teams
 
I like the Wellington.

Construction should be simplified due to the shape of the fueslage.

We can split into 2 teams and work on both the DHC-4 and the Wellington. If we are all ready to start, I'll start up 2 threads, one for each project. I'll list their names here when they have been created.

Everyone is welcome to participate in the design of each of the planes. At the end you can choose which one to build (maybe both? ;) )

-Q.

Quote:

Originally posted by RC_Eflyer
So we're going to form teams or are we all individuals. And can we design something, though equally cool? Such as a Vickers Wellington. :)

--Paul


RC_Eflyer-RCU 12-11-2002 01:50 AM

"Open" design
 
Twin 400s is an excellent idea. I had a 30 amp contoller in my Multiplex Twinstar. I want to be on the Wellington team. :D

--Paul

a088008 12-11-2002 08:49 AM

Scale?
 
Ok. I'll create a thread for the Wellington once we have decided on a scale. Do you have a source for 3-view drawings of the Wellington? We can use them to decide on the scale i.e. wing area needed to support the twin 400's.

-Q.

Quote:

Originally posted by RC_Eflyer
Twin 400s is an excellent idea. I had a 30 amp contoller in my Multiplex Twinstar. I want to be on the Wellington team. :D

--Paul


a088008 12-11-2002 08:58 AM

Vickers Wellington Data & Views
 
1 Attachment(s)
Here is some data I found on the Vickers Wellington:

(found at http://www.nucleus.com/~ltwright/welling.htm)

Wellington Mk.IC Data
Crew : Six
Engines : Two, 1000 hp Bristol Pegasus XVIII
Span : 86'-2" (26.26 m)
Length : 64'-7" (19.69 m)
Height : 17'-5" (5.31 m)
Empty Weight : 18,566 lbs. (8,422 kg)
Loaded Weight : 29,500 lbs. (13,381 kg)
Maximum Speed : 235 mph at 15,500 ft. (4,724 m)
Ceiling : 18,000 ft. (5,486 m)
Range : 1,200 miles (1,931 km) with 4,500 lbs. (2,041 kg) of bombs. 1,550 miles (2,494 km) with 1,000 lbs. (454 kg) of bombs.
Armament : Two 0.303" machine guns mounted in both the front and rear turrets. One 0.303" machine gun mounted in the beam gun position, one each side of the aircraft. Maximum bomb load 4,500 lbs. (2,041 kg)

Here are three views drawings (found at http://www.nucleus.com/~ltwright/3vwelli.jpg)

a088008 12-11-2002 09:32 AM

DHC 4A "Caribou" three views
 
1 Attachment(s)
Take a look at this site:
http://hedgehoghollow.com/ipms/caribou/

I found some three view drawings of the DHC 4A "Caribou" at (http://hedgehoghollow.com/ipms/caribou/caribou1.jpg):

a088008 12-12-2002 06:25 AM

DHC 7A Caribou specs and 3 views
 
1 Attachment(s)
I've also found info on the DHC 7A "Caribou":

C-7A Principal Dimensions

Wing Span 95 feet 8 inches
Length 74 feet 0 inches
Height 31 feet 9 inches
Maximum Gross Weight* 28,500 pounds
Powerplants (2) Pratt & Whitney R2000-7M2

* Normal operations - 33,000 pounds for ferry operations


Here are also three views of the DHC 7A Caribou (notice that the nose on the 7A is different to that of the 4A):

(found at http://www.c-7acaribou.com/c7a_aircraft.htm)

rahtware 12-13-2002 04:44 AM

"Open" design
 
Ever wonder why the tail is so high in a Caribou? I think I know why.

I watched one take off from a jungle strip in Thailand in '67. Halfway down the short dirt strip the pilot pulled the nose up HARD. I thought the tail was going to hit the dirt. As soon as it's nose was pointed up, the Caribou shot up into the air like deer with a hound on it's tail!

Very impressing!

a088008 12-13-2002 06:05 AM

"Open" design
 
I had a hunch it was for takeoff. Let's hope the model does something similar. It should be something to draw a crowd at the field, especially if we make it big. I'm hoping twin 400's will support a 72" wingspan :) and retracts. :D

Quote:

Originally posted by rahtware
Ever wonder why the tail is so high in a Caribou? I think I know why.

I watched one take off from a jungle strip in Thailand in '67. Halfway down the short dirt strip the pilot pulled the nose up HARD. I thought the tail was going to hit the dirt. As soon as it's nose was pointed up, the Caribou shot up into the air like deer with a hound on it's tail!

Very impressing!


liteflyer 12-18-2002 06:07 PM

Wellington design project...
 
Hi fellas. I have been reading your posts concerning the design projects and I am very interested in what and where your going. I have just completed a twin engine design of my own which I call the STORK. iIt is powere by twin 4:1 geared 280's and I test flew it back in Oct. I am also in the engineering feild and have been on AUtoCad since 1990 and am currently running R14 at home and 2000i in the office. My stork plans are completly done on CAD. I am currently designing an almost exact scale Junkers 188E twin engine bomber with very easy and similar framework as my stork as that worked out extremely well. It will be powered by twin geared 3.21:1 400's amd have a span 0f 60". My STORK has a span of 54". As an input to your design project, particularly on the Wellington, both of my birds have scale like langing gear and I love taking of from the ground and hate hand launching! With all the wing area of a bomber, it seems like such a waste to ignore LG... I would like to participate in your design of the Wellington and have copied the 3-view that you have posted. Thanks for that. I am in the middle of a move right now but will be able to support the effort in a maximum way shortly, after the holidays and until then we could discuss the desigh issues and featres desired... You can see a picture of the STORK in my post titled "New twin engine fun fly bomber"....... Keith :

a088008 12-18-2002 06:57 PM

Scale?
 
Great to have you on board.

I've been looking at the "Caribou" and would like to find better drawings than the one I posted. They are a little "rotated" (maybe 1 degree clockwise).

I guess we need to start with scale. I'll look at the Wellington soon. Does a 60" wingspan for the Wellington sound like a good ballpark for twin 400s. I intend putting gears to my motors, so maybe approx. 70" might be a possible wingspan. What do you think?

-Q.


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