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Listed below are some answers to some frequently asked questions along with some general information.
Don Lapinsky of California has a video
about building his Special that is available for $10.00. He says it has
many tips for helping a builder along. Write him or call (818) 892-9324
for more information.
Don's plane can be seen in the Dec, 97 Sport Aviation
(pg 123).
Mike Kindon's plane is the blue one that you see at the RagWing home page. He is using a Rotax 503 for power. Mike lives in New Zealand and here is what he says about his plane.
"...my a/c handles like a cub on the deck, no brakes doesn't
present any problems until I taxi onto a concrete apron,in the air its
crisp in roll,soft in pitch,requires very little rudder to balance turns,flys
slightly nose high in cruise,visibility on finals just like PITTS(awful)"carrier"
type base/finals are best, all landings are three point, take offs are
"flown" off at 50mph.My a/c is NZ spec microlight (your experimental)weighs
380 pounds (I'm 215 pounds) stalls at around 45mph (no clean break,just
sagg/mush) I climb at 60, cruise at 75/80 mph at 5500rpm ,it tops out at
level fight at 95/100mph at 6500rpm with 2.5:1 g/box and 68 inch ground
adjustable prop .CG with me in it is on the aft limit when there
is little fuel in the tank and this is with the battery mounted under the
motor (electric start) and a 10lb block of lead under the most forward
part of the mount, yes I agree It would be hard to make a nose heavy RAGWING
SPECIAL! REGARDS/MIKE."
Q. I've now finished my wings to the point of gluing the
leading edge plywood to the noseribs, and that's what I have
some questions about. Did you wet the plywood to bend it around the small
diameter curve the noseribs? Did you varnish the inside/interior
of the plywood, before or after gluing? And how did you varnish and
still leave the areas for gluing bare of varnish, so that the glue holds
as it should?
A. Build a form by cutting some 2 x 6's to the shape of leading edge ribs and screwing to a long 2 x 6. This form should look like the wing from the spar forward and be as long as the ply is. The shape of the ribs should allow for the plywood to be over bent about 5 degrees or so (taper back slightly from the L/E back in a teardrop shape). Soak the plywood thoroughly for at least a couple of days. If you have a swimming pool, it will work great, if not, I built a frame of scrap 2 x 4 approx. 3' x 6' and stapled a liner of plastic to it to form a big enough trough, then filled it with water and weighed down the wood to keep it covered with water. Some in our EAA chapter recommended putting in a little ammonia to kill bacteria and to help soften the wood. Keep the water fresh or you will get dark stains of mold on the wood. When completely pliable, form over leading edge form and clamp in place. Allow the wood to dry completely (2 or 3 days) then remove. The ply should be slightly overbent so when it slips onto the wing it makes firm contact everywhere. Before soaking & bending, mark the inside of the ply where the ribs and leading edge stiffener will glue with a pencil line. After bending, apply a piece of 3/4" masking tape along these lines and apply varnish everywhere else. When gluing the wood to wing just apply glue to all the areas that were covered by tape and you will have complete protection.
David Morrow RWS #67
Q. I made the leading edge 2 X 6 form you suggested. Works great! I have formed two 3 ft. pieces by soaking them in HOT, HOT water in the bath tub for about 4 hours, and then clamped them to the form. I learned the hot water thing while laminating the tailfeathers. Now I just don't quite know how I'll soak the 5 ft. pieces. They won't fit in the bathtub. The pool's frozen over now! I might roll up bath towels and pour boiling water over them and the wood while over the tub....I'll have to think about it a little, before I bend the longer pieces.
A. Are there any suggestions for Dennis? Lets here from
some other builders.
Q. Greetings to all from Ev rws #306. I elected to put some curve into the tail section of my plane,(as opposed to flat sided) and am having to deal with some interference with a diagonal and upright when running cable to the bellcrank. The problem is not unsolvable but I was just wondering if other builders had run up against this and would be curious as to what they might have done in that situation. I do not want to alter the length of the bellcrank because I feel that would disrupt the geometry that the designer intended for that aircraft. Thanks.
A. I had the same problem and installed cable guides at the upright at station 98. I bought the guides from Leading Edge Air Foils, P/N D2300 $1.00 each (1995 price). Any other solutions?
David Morrow RWS #67
Q. I'd really like to see how you did your instrument panel. I guessed the .080 6061-T6...do you think that will be thick enough? I didn't really consider that I'd have to cut holes in it which might make it weaker...and a hard landing might bend it (I'm using a certificated altimeter which is pretty chunky).
A. My panel is made from 3 mm plywood screwed to a laminated wood support using aluminum wood screws. I'm using a Cessna altimeter from a 172 and the panel supports it just fine. .080 alum should do real well. I now have my compass (backup compass from a Airbus A320) mounted under my center mounted airspeed indicator.
David Morrow RWS #67
Q. How did you protect your steel brackets. I think I'm going to have them nickel-plated so they're shiny and well-protected, but I'd like to hear how others are doing it.
A. Nickel plating is sure expensive. A slightly cheaper way is to cad plate (type II class 2) then epoxy prime. I went the cheapest route and chromic acid etched then applied epoxy primer.
David Morrow RWS #67
Q. Where did you get your fuel tank and what size tank are you using? I sent off an e-mail to Fisher Flying Products and they have two that they'd sell me that seemed like they'd fit.
A. This I bought from TEAM. It's a 5 gal miniMAX wing tank and fits well under the cabanes. I extended the filler neck through the turtle deck alum. and added a fuel filler neck seal from an MGB so spilled fuel would not leak back inside. If FFP has one that will fit and not require modifications, get it instead. The TEAM tank does not have a sump so I added a 12 oz header tank on the firewall in case the fuel pickup comes uncovered at nose down attitudes with little fuel.
David Morrow RWS #67
Q. Did you get your cowling from Roger (Mann)?
A. My nosebowl came from Roger but the cowling was made by me from .020 sheet. Since the accident, I'm rebuilding it from .025 to get some additional weight forward. Everything from the longerons up is sheet covered to allow for access.
David Morrow RWS #67
Q. I really liked your windshield installation...where did you get the windshield and how did you attach it?
A. The windshield is a piece of 1/8" Lexan and attached with 3 alum. angles bent from 1/8" x 3/4" flat stock, 1 in center and 1 at each corner like a miniMAX. I believe it took a 1 x 2 ft piece I bought at a local plastics supplier for $12.00. I am adding a rubber seal around the bottom edge. With the curve built in it becomes fairly strong, although I wouldn't trust it at 125 mph. I cut many a cardboard patterns before settling on this one.
David Morrow RWS #67
Q. Dave, I believe Roger no longer produces a kit for the Ragwing special but gets some one else to make it up and ship it........is the kit as good or worse or better?.....drop me a line if you have heard how the new kit is, thanks.
A. I heard rumors of someone else doing the kits, but
I have no information about them.
Does someone else has any info?
Q. I like the idea of the sheet metal for the turtle decks and cowling but, how did you attach it to the wooden structure? Did you have to bend the metal to lip over the firewall? Also, where the cockpit metal came in contact with the turtle deck did you use rivets?
A. All the sheet is attached using Truss Head Type sheet metel screws. I used #4 x 5/8" Type "A" where the screw passed thru the sheets into wood and #6 x 1/2" where it screwed into metal and #8 x 1/2" Type "B" screws into "U" type Tinnerman nuts to hold the cowl to nose bowl and to fasten the turtledeck covers together. The 3 turtledeck covers attach to themselves under the cabanes and have no stringers or additional support. They are curved and are quite rigid. I did not bend any lip as the rear most piece around the cockpit goes on first, then the turtledeck, then the engine cowl. Mine overlap 3/4" and the top and sides of the cowl are screwed into alum angles attached to the fire wall. You should be able to screw directly into the vertical behind the fire wall with no problems instead of adding the angles. Use Stainless Steel screws. I don't think I can explain exactly what I did in detail enough for you to fully understand. This is my problem and is a shortcoming with my writing abilities. At the moment I don't have any really good pictures showing any detail, but will get some as soon as possible and get them to you. See the photos of my plane at my web site and maybe they will help.
David RWS #67
ps: when I refer to the turtledeck, I'm talking about
the area under the cabanes, not behind the cockpit. I used ply like the
plans call for in this area.
Q. Hi David,and fellow builders,... I looked over your
cowling pictures with interest and couldn't help myself from wondering
if any if the other builders out there had considered using composite
material for the rear deck and the turtle deck/cowl combination.
It seems to me that if any weight savings could be realized from
this, then the extra time and expense would be worth it. Has anybody
with any experience done the math?
A. It depends on what kind of composite your talking
about. Regular fiberglass will be heavier than aluminum. Don Lapinsky says
that he used a composite (carbon fiber, I think) rear deck from a Pitts
1 holer. It was prefabricated and he says it fit perfectly. I don't know
how much they cost, but should be very light. I personally never considered
any composites because of their high cost.
David Morrow RWS #67
Q. I would like to know what (if any) adjustments you made in the angle of incidence of the horizontal stabilizer. Did you set it up exactly like the plans call for? Also, at takeoff, are you able to get the tail up or does it fly off from a three point attitude?
A. Tail incidence was packed up a further three quarters of an inch to get hands off at 75mph at 5500 rpm...yes I'm pretty sure I had the tailplane incidence set up per the plans originally. I've always taken of by poling forward a couple of inches as I've opened the throttle...the tail soon pops up and rotates shortly afterwards...I've never tried the three pointer take off because of the poor viz over that long snout....but the prototype did so fine! so it should be okay.
Mike Kindon RWS #70
Q. I just finished drilling the 1" hole in my spar carry-throughs, and inserted the 1' Al. torque tube to get an idea of what everything will look like. The trouble is, I can't figure out where the elevator push-pull tube is supposed to go through! The rear spar carry through is solid (i.e. no holes), and the seat back is right above it, so it doesn't look to me like there's any route for the elevator tube to get to the rear of the aircraft. I looked at your aileron mixer photo but couldn't see where the elevator tube goes....any help you could offer would be much appreciated!
A. If you have the 1st video, review it for some help. You are right, it's not in the plans (along with other things). On fig. 9 there is a 1" dia hole noted in the rear carrythru, but there should be 2, one on top and one on bottom at 1-1/4" from each edge to center. The top hole is for the push-pull tube. I made mine a little larger (1-1/8" dia) but don't cut into the top 3/4" piece. Also look at fig. 28. The section view shows a larger hole at the top.
David Morrow RWS #67
Q. That second hole sounds good...I can see it later in the plans but was unsure of the details. Does the 1 1/8" hole give enough room for the elevator tube to move side-to-side when the ailerons are deflected? It seems like there would have to be a horizontal slot in the rear spar carry-though. The only thing I've had trouble with was the spar attach brackets being 1 1/8" apart (3/4"spar + 1/8" web + 2 X 1/8" doublers) but the carry-through being just 1" (3/4" spruce + 2 X 1/8" doublers). Roger said to add washers underneath...how did you solve it?
A. 1-1/8" hole is enough for the amount of movement the tube has at the forward end. You can slot it a little more if you like. I glued a piece of 1/16" ply that is slightly bigger than the wing straps to the front of the front carrythru and the back of the rear carrythru. IMHO they are not really needed and really make it harder to mount the wings. Just don't tighten the bolts so much as to squeeze the straps against the carrythru.
David Morrow RWS #67
Date: Fri, 12 Feb 1999
Conrad Nordquist asks:
Q. ...I have a question about wing ribs. I've finished
over 20 ribs and now wonder about the 'false rib' noted on the drawing
Fig 2 "false rib
starts here, 2 req. lower wing." handwritten at bottom
of sheet. That sounds like the root rib for the top wing of the Special,
but the plans, Fig 2 "18 ea. top wing" seem to call for 18 full ribs for
the top wing. The plans also call for only 16 ribs Fig 3 "16 ea. bottom
wing" handwritten at top of sheet. for the bottom wing, but it seems to
me that 18 are needed including the root rib. Where is my confusion here?
Can you help me out?
A. The false rib goes outboard of the last rib and attaches to the aft side of the rear spar. The last rib becomes part of the aileron and the false rib becomes the attachment point for the tip bow. Figure 20B shows how this works although it doesn't have any dimensions. I set mine to leave 1/2" space between the aileron and this false rib to ensure no binding and to facilitate removing the aileron and to give clearance for the hinge bearing and bolt. The lower wings are 1 bay shorter then the upper wings so only need 16 ribs. The fuselage width makes up for this.
Also, if you use a socket head cap screw that is the size of the bearing O.D.(1/4" shcs I think), slot the center hinge support at the aileron attach point, then the aileron will be removable by taking the inboard bolt loose and you will not need any access holes in the aileron to install or remove. This is ala TEAM MiniMax and works very well.
David Morrow RWS #67
