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Old Oct 10, 2002, 06:35 AM
Over Engineered
Robert Hoffman's Avatar
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Let's Talk Camel's!!!!!!

Vintage1
Sounds to me like you are looking at a construction simular to FF rubber power. I think that is kind of what Dare Design does. Are you talking 100% Stick Built?


These links are Pup rigging drawings:
http://members.rogers.com/british-ac...h_Pup_3of4.jpg

http://members.rogers.com/british-ac...h_Pup_2of4.jpg

http://members.rogers.com/british-ac...h_Pup_4of4.jpg


I am not sure but I think the weight of the rigging is less but the drag is more.
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Old Oct 10, 2002, 07:13 AM
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Yes. A stick build twill be.

Here is the drawings so far..
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Old Oct 10, 2002, 07:14 AM
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and the wing plan....
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Old Oct 10, 2002, 07:20 AM
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Vintage 1,
Since we're talking Camels here, this seemed the best place to reply to your other query.
Although I'd never given the rotation question much thought, I do know that the cut outs in the cowl were for additional cooling. They were often field mods, and varied in size and position.

As for your s400 Camel, is that a geared 400? If so, a total weight of about 20-24 oz would be fine for your model. That's no problem without the need for an ultra light wing structure. In all probability, you'd add more weight with the rigging points for working rigging than you'd lose by reducing the amount of wood in the wings.
As anyone who knows me will testify, I never build one model from a design if I can build two, so was already thinking of scaling the Camel down to 36". It would be interesting to compare notes as your's proceeds. Mine is likely to take a bit longer, but will use a 2.33:1 geared 400 and seven cells. Even the small one will have ailerons on all four wings - just as it should.

Pete
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Old Oct 10, 2002, 07:24 AM
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I'm shooting for AUW of about 22oz with Sp400 6V 3:1 and 10x7 prop (scale diameter) on 8x600Aes. 37.5" span.

Full house controls. DEFINITELY ailerons since I want it to roll ...

Motocalc gives that more than adequate power.

I'm happy to get to that sort of figure, but less sure about the short fuselage and small tail moment. Looks like it might easily do a 'death spiral' if the CG too far back :-).

Areas I could use advice on, are how to get those wings light...BIG wings. I want to use silk, but will they be strong enough to stretch the covering over? Should I use rigging wires to stop them folding?

And, I don't *really* want to stick a bigger rudder/fin on, but am I asking for unrecoverable spins with such short moment arms...I want to stick to scale dihedral and areas if I can, but am happy to go with a simpler wing section. I'd certainly rather have a 'neutral' plane than one that dutch rolls...
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Old Oct 10, 2002, 07:25 AM
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Vintage 1,
Wings look pretty good, but fuselage shape could use a little rethink. What drawings are you using for reference?

Pete
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Old Oct 10, 2002, 07:31 AM
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Quote:
Originally posted by PETERRAKE
Vintage 1,
Since we're talking Camels here, this seemed the best place to reply to your other query.
Although I'd never given the rotation question much thought, I do know that the cut outs in the cowl were for additional cooling. They were often field mods, and varied in size and position.

As for your s400 Camel, is that a geared 400? If so, a total weight of about 20-24 oz would be fine for your model. That's no problem without the need for an ultra light wing structure. In all probability, you'd add more weight with the rigging points for working rigging than you'd lose by reducing the amount of wood in the wings.
As anyone who knows me will testify, I never build one model from a design if I can build two, so was already thinking of scaling the Camel down to 36". It would be interesting to compare notes as your's proceeds. Mine is likely to take a bit longer, but will use a 2.33:1 geared 400 and seven cells. Even the small one will have ailerons on all four wings - just as it should.

Pete
Hi peter. You are not so far away. Maybe I can see yours fly one day?

As detailed, 3:1 sp 400. I had a spare 6v motor so have strapped on the Irvine open frame box, and want to use 8 cells in case it needs nose weight and/or extra power.

Thanks for 'cooling' info. Maybe i'll put a hole there for the same reason.

Mine has ailerons everywhere too. At that slow flying speeds anticipated (sub 20mph) models get tossed around in the breeze a lot. I am thinking of using a single HS80? servo in the lower wing root with snakes going to the lower ailerons, then simple pushrods to couple in the upper ones. Hs55s for elevator and rudder, cos I have some spare..

I'll take your advice and build the wing strong, but will probably rig it anyway - its only 'sport scale' so a bit of guitar string tensioned up with a small spring inside the fuse. and cyanoed to a bit of ply in the wing willl probably do for me...
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Old Oct 10, 2002, 07:33 AM
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Quote:
Originally posted by PETERRAKE
Vintage 1,
Wings look pretty good, but fuselage shape could use a little rethink. What drawings are you using for reference?

Pete
An crappy 3 view I downloaded. What specifically looks wrong?
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Old Oct 10, 2002, 11:21 AM
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Vintage 1,
It would be great if we could get together for a flying session some time. Our site has 24/7 access which helps - except at night of course. Landing lights drain the battery too quick.

Now, about that fuselage. It's actually easier to tell you what ISN'T wrong with the shape - the cowls not bad and the fin/rudder look reasonable. It's the bit in between that's the problem, looks more like a Snipe than a Camel. You'll see what I mean when you look at a decent drawing. If you think that looks aggressive and stubby, wait till you see a Camel proper. PM me your e-mail address and I'll let you have a copy of the 3 view I worked from.

Just an idea, but I usually find a totally flat bottomed wing works well on these models. Your's looks to be more semi.

Pete
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Old Oct 10, 2002, 01:36 PM
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YHM.

Wing section will probably be flat bottomed, and deep enough to take some decent spars.

I also have 24x7 access to a field - its 10 feet from the house. Currently 'set aside' for the next year...but full of stubble :-(

Hand launch only and drop in whatever bit of rough looks less spikey.

Still a nice sturdy UC should keep most of the bits clear of the ground, and camels were famous for nosing over. Does rule tissue and litespan out tho.
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Old Oct 11, 2002, 07:25 AM
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Camel Facts??

Is it true that the name "Camel" was given to this design because of the cover over the guns made it look like it had a hump?

Also I remember hereing that the Camel had a tendancy to do tip stall spins and were difficult to recover from them. Is this true as well?
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Old Oct 11, 2002, 08:57 AM
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Well..with a thin wing with quite a large span, and a small fin on a short fuselage..I would NOT be surprised.

I guess I will find out the hard way.....

IS that a gun cover then? Maybe that where my drawing went crooked.

Yes. I foun some photos of the cockpit area. All makes sense now. The cockpit is higher than the cowl, and extends forward to cover the guns - at least partway along.

Apparently that's the 'hump' that gave it the name.


There appears to have been a removeable cover on the left hand side of teh cowling as well.

Oh boy. Here is a site for camel freaks

http://www.pilots-n-planes-ww1.com/A...l/SW-Camel.htm

I have looked at many sites - and one modeller who built an accurate scale version reported no handling vices at all?

Oh well

I also found a weird japanese site that had a bare frame of the whole thing - can't read Japanese, so I don't know if its real or not, but it looks like an accurate rendition of every spar and rib...
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Old Oct 11, 2002, 11:58 AM
Over Engineered
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I found the text on Camel's flight

An agile, highly maneuverable biplane, the Sopwith Camel accounted for more aerial victories than any other Allied aircraft during World War I. Credited with destroying 1,294 enemy aircraft, it was called the Camel due to the humped fairing over its twin machine guns. Much like a real camel, this aircraft could turn and bite you. Noted for its tendency to kill inexperienced flyers, many pilots feared its vicious spin characteristics. Until sufficient speed was developed during takeoff, Camel pilots maintained full right rudder to counteract the torque the rotary engine. Failure to do so often resulted in a ground loop with the Camel crashing on its starboard wingtip. During World War I, 413 pilots died in combat and 385 pilots died from non-combat related causes while flying the Sopwith Camel.

A Camel Pilot Said,
"A great number of trainee pilots had been killed learning to fly this machine, as its tricks took some learning, although they were really simple to overcome. Its main trouble was that owing to its very small wingspan, and its purposely unstable characteristics, coupled with the gyroscopic effect of a rotating engine and propeller, it flipped into a spin very easily at low speeds. Consequently, in landing and taking off, a tremendous number of fatal accidents occurred, and a general felling of dislike for the machine was prevalent. It really had people frightened."

Another neat fa ct:
Canadian ace Roy Brown was flying a Camel when he was credited with shooting down Manfred von Richtofen.

This information is from the Aerodrome Home Page.
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Old Oct 11, 2002, 12:46 PM
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If I read that bit once, I read it a hundred times today...I must have been through over 60 pages of sopwith camel sites - most with teh same pictures and the same words on em.

I did find one interesting article somewhere, where the question came up, and the author reckoned it was a combination of things - the gyro effect of the rotary, the torque of the very large prop, the mass all concentrated around the CG, the very thin wing section, the small fin, and large rudder area that could flap if the pilot didn't tread on it, and a rather aft CG that made the thing pretty unstable and liable to drop the left hand wing in a hurry.

One modeller reprted that the model - I think it was in fact the old Mick Reeves design - 'had none of the vices associated with the original'.

Looking at the above list, only the short moment arms and the small tailplane are liley to be issues. I can mess up the wing section (and will) and although the torque will be bad on a scale prop, the gyro effect is not there. Anyway, I can mix in rigfht rudder with throttle if I have to.

Unusually the modeller reported it didn't really need ailerons to turn. The dihedral was enough to ensure that rudder was required, and ailerons fairly superfluous in the turn. Oh well, we will see...
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Old Oct 11, 2002, 12:55 PM
Over Engineered
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Tail Length

There was a discussion in the past on this forum about the DR1. They talked about different designs they have seen in models and the affect on nose over. The common item was that the higher third wing raised the cg. This with tyhe stubby tail added to the instabillity. The one design that appeared to eliminate this had an extended fuse to get a longer moment on the tail. They also were very carefull to design an extra light top wing. This was to lower the cg. They also moved the landing gear slightly forward to help with the nose over. This may have had an effect on the tracking during ROG until the speed was up enough to allow the rudder to be effective.
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