Tritle's Bristol Boxkite/Farman Type IV

[E-Challenged]

Here are some preflight pics and info on Pat's Tritle's latest R/C scale antique design. I'm posting this for Pat who still hasn't been able to get re-registered on E-Zone

The Bristol Boxkite, AKA Farman Type IV Standard Biplane, are one and the same. Henry Farman actually designed the airplane, but it was built under license by Bristol, 135 in all. And, it was an early Farman Biplane that won the Grand Prix at Rheims in 1910 with a flight of 3 hours 5 minutes. it was the same air exhibition where Curtiss set the Speed record in the "Rheims Flyer" at just over 46 mph.
Type IV. The model spans 35", is 32" long, and weighs in at 9.2 oz with a 150 7 cell battery. Wing area is around 420 sq in with the wing loading around 3.2 oz/sq ft. I used an old TA 14W power system with 5:1 gearing with a Contronics 6-10 ESC w/BEC and a 9-6 GWS prop. The 4 channel control system is driven by 3 servos. The rudder and ailerons are cable driven, and the canard is hooked up via a pushrod with the elevator slaved to the canard by cables. All the cables are routed through guides made from1/32 I.D. aluminum tubing. The model is covered with buff litefilm and sprayed with satin clear to dull it down. The struts and fuselage frames were stained with Ipswich Pine stain and varnished and the rigging done with 40 lb test kevlar "Spider Wire". I wound up making the wheels from balsa & ply discs and paper cones. Plastic prop bearings for rubber models were used for the wheel bearings.

Pat hasn't flown the model yet, as soon as he gets it flown, I'll post the full report and send along a couple of inflight photos. As lightly loaded as the model is he, really doesn't anticipate any problems. Once the project is completed, it will be going to RC Micro Flight for publication as a construction article. And, as always, laser cut parts will be made available from Teccut in Baltimore.

[E-Challenged]

Cute, huh!

[Greg Smith]

Gorgeous model, although typical for Pat. Looks like a good LiPo battery candidate too (those flat batteries could hide easier in the sparse structure). This is electric modeling at its best - a glow version of such an airplane I can't imagine.

[sky guy]

Wow! beautiful model. Pat's miniture aerodrome is really growing fast. He must be gearing up for a remake of Those Magnificent Men in their Flying Machines

[Greg Smith]

Must be. A Boxkite reproduction was one of the mechanical stars of that movie, dubbed the "Phoenix Flyer " in the film.

[E-Challenged]

Heres the gist of his e-mail re first test flights:
" I snuck out between gusts this morning and got 3 short but very cuccessful flights on the boxkite. Unfortunately I went alone on the spur of the moment so no photos were taken, but I'll be going out with a friend next week and get the shots.
The model, though will require a small amount of "tweeking", flies beautifully. Much to my surprise, there is little or no adverse yaw from the ailerons, and it also turns fine on the rudders alone as well. Elevator input doesn't exhibit any of the sensativity that I anticipated from the canard, and it has more then adequate power since I changed from the TA 14W drive to the GWS A drive and 9-7 prop. Also, there were no adverse effects from operating 3 servos with the small BEC controler. At this point, the only thing I can see that needs imediate attention is the CG location. With 4 or 5 more flights, I should have that pretty well noodled out so I can get busy finishing up the plans and paperwork for the article. At this point the basic design looks sound. Can't wait to get you a couple of photos. You would have to see this thing floating around at 4 feet of altitude to apreciate it. Flight characteristics are similar to the Curtiss, but it has a much lighter feel, and I really think it could be flown in a gym."

[Greg Smith]

Please let us know when the plan is published, I'll definitely consider renewing my subscription to the mag.

[E-Challenged]

Here is Pat's latest Flite Report, pics attached:

"Been flying the Boxkite a lot, and have it pretty well figured out. Got some good inflight photos this morning, which I will attach.
The model has 16 flights on it now using both a 150 7 cell ni-cad and and a 300 8cell ni-mh. The 8cell overpowers the model enough to make throttle management critical, but once you figure it out, the duration creeps up around 7 minutes.
Flying the model is really a blast, but as I mentioned, throttle management is important. As you throttle up, the nose drops do to the extreme lift produced by the airflow over the undercambered tailplanes. Then, as you throttle back and the lift is reduced the nose will rize. Through much testing, I've discovered the optimal CG to be at 50%, which contributes to the tail sagging at low throttle. But, while all that's going on, pich control is docile yet effective, and the airplane doesn't exhibit any "unstable" flying qualities. For the reasons described, the model is landed at "slow cruise" power, and by holding the nose up slightly, a good manageable sink rate will always result in a smooth 3 point landing.
The Boxkite has some of the most unusual flying qualities of any airplane I've ever flown, but at the same time is among the most stable and forgiving. Those guys that were designing these old airplanes must have really had a good "seat of the pants" feel for what they were doing.

[E-Challenged]

Here tis!

[BEC]

Ah, those New Mexico skies!! And what an aeroplane!

Pat oughta try a two-cell pack of ET700 LiPolys or Kokam 1020s on that airplane then - if 7 cells of nickel batteries provides the right power.

I need to plan to visit Pat when I'm back in NM this summer!

[max z]

Gorgeous! What a stirring sight. It would not be hard to imagine it is the real thing skipping the tree tops behind the house, if it was not for the pilot being out for lunch Terrific model, congrats to Pat.

Max.

[Greg Smith]

It looks like this model has as much visual impact as say the Wright 1903 or Military Flyer models, in terms of shouting "early aviation scale model". However I would guess it is a little easier to build and fly. I would be interested if Pat has any comments on this.

[E-Challenged]

I'd like to see Pat develop a nice Bleriot design, after he does the Urpcup ( Ercoupe), Cessna 140, and other great stuff he has in the pipeline.

[Greg Smith]

The plan build ariticle has been published this month in Backyard Flyer. Finally a reason to buy that mag.

There is a photo sequence of construction at http://www.backyardflyer.com/

This model is very, very tempting.

[kdhanson]

Yes, Pat's done it again! I have the plans on order from Air Age and it's going right to the building board as soon as they arrive.