return to thumbnails
Date: Mon, 20 Apr 1998
From: Chris Parent
Many thanks for the feedback via FFML and regular e-mail on the photos on Thayer's page. I'm kinda surprised by the number 'o questions via regular e-mail. I'm far from an authority on the subject, so please take the following as humble musing. Also, if you spot anything stupid I'm doing, please mention it.
This is long. Skip the dull parts.
Probably better that I can make them. Yesterday morning was very calm so the Ryan, Staggerwing, and T'Mustang went up.
I'm not yet much of a flyer so I struggle with trim. For the most part I fight with a twitchy model before finally adding the lump or lumpette of clay it really wants up front.
The Ryan does 55 to 70 seconds on 1250 turns 8 x 32" strands 1/8 rubber lubed with Peck's lube. ( I bought the $$$ tube of Dow 33, but haven't tried it yet.) Left, left. Big and very predictable. I don't have a good scale but it is about 75 g w/o rubber. 9.5 Pecks prop with the pitch opened up.
The Staggerwing is still in the trimming phase. I want to use it in an indoor meet on Sunday. Best seems to be 2 strands of 1/8 + 1 strand of 3/32 (can't afford a stripper) 26" long. I've done some ~30 second trim flights. I'll try to tweak it on Sunday. Boy are those hinged surfaces handy. I forget the weight (I'm at work), but I remember being happy about it. 7" Pecks prop cut down to ~6" and thinned a lot.
The Thunder Mustang peanut flies really nicely. 2 strands 3/32 rubber 21" long. Did slightly more than a minute on 1400 turns. I'm sure it's capable of more. I might try a different prop. VERY thin airfoil, maybe 5/32 at the root and 1/16 at the tip. (At these Reynolds numbers the stall angle must be very low, so why have a thicker/ higher cambered wing for angles of attack at which the wing will never fly? This at least sounds good.) I think it is 12 g w/o rubber. I'm guessing this is a little heavy but I like the look of the pilot, so it stays.
I get much flying advice from the guys up here, this is why they don't all torque roll and land on a wingtip.
I have hinged all the tail surfaces with twist tie wire. The weight gain seems minimal and the trimming advantages are huge for me. (I am a relatively inexperienced flyer.) I tried hinged surfaces on a Wildcat and was so pleased with the results that I'm a permanent convert.
For roll trim control I set up with a level left wing and a gut feel level of washout on the right. I can then adjust rudder, elevator, CG, and thrustline to balance. If the circle is much too big (or small), I tweak the washout over the kitchen stove. For the Pitts, I wish that I had made real ailerons since the wings are hard to tweak once the struts are glued in. Of course I could have left the struts off during trimming, but that would require prior planning, patience, maturity, etc...
For this reason, I made hinged ailerons on the Albatros. This is particularly silly considering that the Albatros has V struts which do not lock the bottom wings in position. I could have easily adjusted using the bottom wings. So to complete the variety, I'm finishing up a Boeing F4-B 4 with non-hinged ailerons and N struts. But, I'll do what worked on the Staggerwing: Only glue the front tip of the upper right strut in place until the washout is flight tested.
3. Finish details
Pitts: - back
24" span: JCI red, airbrushed butyrate white. The dope shrunk too much. I won't do that again. Markings are JCI red first doped then cut out and applied with white glue/water. Nose block is covered with tissue, then airbrushed white. The wheel pants are covered with JCI red. 2 pieces, left and right for each pant. By using a thin white glue and water mix a huge amount of compound curve is possible. I also sit in the lotus position under my special modeling pyramid. Do most of the pulling with the grain, and be ready to make about 10 attempts for the 4 pieces actually used. Rigging is heavy elastic thread colored with a gray magic marker.
Albatros: - back
22" span: JCI everything. UHU stick adhesive for everything. (Purple UHU, white UHU, other brands all work just fine) Most tissue applied wet, then tacked down on the perimeter with a monocote iron. This is why all brands of glue work, you get the glue dry with the iron before the wet tissue shrinks. Crosses are cut tissue applied with UHU. A problem actually. The crosses continue to shrink for a few days and make small wrinkles in the tissue. Bavarian lion is hand painted on white tissue, and looks sloppier in real life than in the photo. Purple is airbrushed over green tissue, masks cut from Post-it notes - comes off easy and doesn't tear the tissue. Pilot is from Small Scale in the UK (Lindsey Smith). Rigging is thin Lycra thread from SAMS, UK. It's very stretchy; I put it on under as little tension as possible. Thus, the exposed rigging can catch on stuff, my thumb for example, without pulling the plane apart. The rigging on the undercarriage is actually strong nylon which was necessary to stabilise the assembly (Gudebrod size A nylon if any of you build fly rods). Engine, guns from balsa. Prop in the photo works lousy. I've since made a new set of blades from 2 sheets of 1/64 plywood laminated to form the curve. Much better. Each blade is glued to a short piece of bamboo which plugs into the hub. Easily changed-Adjustable pitch. Doesn't show in the photo, but there is a fancy-schmancy shock absorbing axle setup, and scale instrument panel.
Also, bizarre "anti-potato chip" laminating on the elevator/stabilizer. Three layers: real thin (maybe .02", I think) basswood on the inside and outside and VERTICAL grain very soft balsa (1/8 or 3/32, I forget) in the middle. It all bends so easy that water or heat are unnecessary. Pretty light and very stiff.
Ryan: - back
30" span: Not much to say about the finish here. JCI silver/Krylon. Wheel pants and nose are balsa painted with Pactra balsa fillercoat and some spray can of silver I had laying around. Markings are hand painted acrylic. Big ones on the wings were easy, little ones on the tail were hard. 1/12 pilot from Small Scale UK. Rigging is the same heavy elastic thread I used on the Pitts. I put it on VERY LOOSE, virtually no tension. This lets the wires under the wing catch on stuff without making a mess. Careful bracing inside the wing has worked excellently so far. Fron the landing gear inward I used vertical 1/32 balsa webbing to make a box spar. The webbing is on one side only of the spar for one rib space outboard of the gear to provide some load transition in case I hit a wing tip. First trim flights were a little exciting, but the gear and wing held up fine. The wing bracing came from comments in FFML in '97 I think. Many Thanks.
I really like JCI tissue but its SO HARD TO GET. I'm avoiding using it now because it can take a very long time for an order to be filled. Don't get me wrong, Jim Calley seems like a great guy on the phone, and his product is well worth the money to me. It's just too hard to get.
Thunder Mustang: - back
13" span: Tissue is colored with chalk, I'm really happy with the effect. Yellow lettering is rub on letters. Rub softly over the open tissue. White letters are squiggly lines of paint. Very light Krylon over everything. Flags (checker and US) are drawn on white tissue. "Streamer" stripes are acrylic paint on tissue, then UHU on the back of the tissue. Let it completely dry, cut out the tapered stripes. Use sparing amounts of isopropyl to glue the stripes onto the plane. Canopy is cut down from the way-too-big Peck's peanut Mustang kit. Canopy stripes are UHU glued tissue. Pilot is from Small Scale with a painted attempt to make it look more civilian.
Staggerwing: - back
17.5" span: Lots of compound curve tissue work on the cowl. Stripes are cut tissue, dried UHU on the back, applied with isopropyl. Rub-on letters. Lycra rigging. My wife and father insisted on the fiddly antenna work on the "roof". They are tissue covered balsa, and remarkably have not broken off yet. Canopy stripes are UHU and tissue. Engine is from Small Scale. Krylon. I'm a real Krylon nut now.
AND,... I'm almost done, really,...
I got several e-mail questions on the photos. It is classic 1982 small product lighting. Studio gray seamless paper, a 3x4 foot soft box directly above, plus a small baffle to make the shadow gradation on the background. Something like 400 w/s is more than enough for 35mm. Pictures are generally cruddier than they look on Thayer's page.
Anyway, sorry for the long one. Many thanks for the feedback, and even more thanks for the endless stream of info and ideas.
gallery index | home page
Copyright 1998, Thayer Syme. All rights reserved