89" Dynaflite PT-19 scratch build..
09-17-2010, 03:32 AM
#29
RE: 89
RCWARBIRDBUILDER, I glued thin plywood to the fuselsge side sheeting to form the bottom of the wing fillets. Then i glued triangle formers (every few inches apart) on top of that sheeting with the top of the triangles radiused. I filled the space between the triangles with a spackeling compound i got at ACE hardware. Then i glassed over all that once i was satisfied with the shape. The spackel would not be strong enough on its own with out the glassing over it. The real strength comes from all the triangle gussets glued from the bottom plywood to the side sheeting. I contemplated makeing a new canopy for mine from scratch to be more scale, but to answer your question no dont know of an after market canopy. There is a new Chipmunk ARF out with that type canopy tho, dont know how close it is to fitting either. Just a thought on motors, i was thinking of putting a G-38 or US 41 in my Chippy, but i bought a NEW DL-50 (off ebay) for less than i could find a used 38 or 41. Its over kill i know but for $200 NIB & it runs great, something to consider. Im enjoying your build & also chatting with you, sorry for the long post......Gene
09-17-2010, 08:26 AM
#31
RE: 89
Gene have you flown the plane yet with the dl-50 if so what did you think? I know I can't find anymore Quadra for sale either... On the fillets I lay the ply like you do and than use balsa tri stock starting with small than going larger as I go back, it is strong but the draw back is the sanding to shape, that is interesting how you do it,,, George.
09-17-2010, 11:46 AM
#34
RE: 89
RCWARBIRDBUILDER, I just maidened it 2 weeks ago.(7 flights on it now) It has to be one of my favorite models i ever built! The DL-50 is in my opinion way overkill, but at full throttle it will takeoff in 30'. I would not hesitate to tell anyone to put a 50 in it. It floats in for landings at a crawl w the flaps deployed. Im running a 22-10 prop right now. My all up weight less fuel is 17-1/2 lbs. I think if i build a PT-19 i will use another 50, the two models really seem to be very similar in size. I did mount the motor as far to the left of the firewall as i could & then brought the spinner back to centerline to counter any torque. I didnt have to add any right rudder trim, it tracks straight. I dont know if the PT-19 has any built in right & down thrust like the Chipmunk, but i KEPT the down thrust angles that were on the plans & just added the extra few degrees of right offset. I fly IMAC & pattern models , so building it to fly straight was allways on my mind. You are really moveing along with the PT-19!! I really wish Dynaflit still kitted both these models. I have never heard anyone have anything negative to say about how well they fly....Gene
09-17-2010, 12:27 PM
#35
RE: 89
Gene, I fly my Chipmunk on a Quadra 35 and on a adverage day it well fly fast at full throtle and make nice large loops without a problem. I flew my Chipmunk last week at a fun fly, the wind was really blowing, and that is when I knew I could use a little more power on manuvers, it flys fine even in the wind but on loops and rolls it could use more power to force it through... I set the Q35 into the PT-19, it well fly it just fine but it does have more drag than the Chipmunk, mainly the fuselage is larger,, before I get to far in cutting the fiberglass cowl for it, I found a used Cermark SPE-43 for a good price today if it runs good, looked up the test results on it and it has a static pull of over 15 pounds turning a 20x8 prop, so that should put it at little under one to one weight ratio, I can live with that. Only thing I don't like now I well have to set another battery onboard for the ignition, George.
09-17-2010, 05:06 PM
#38
RE: 89
George, Im running 3 - 2600 li-po packs on mine. One for ignition and two for the reciever/servos. If you look at my chippy pics closely you can see the switches below the cockpit & just behind the cowl on the other side. I didnt try and hide them and get razzed all the time for it. I finally got my pilot today & gotta get him in there cause i hear about that too. We have a tough bunch round here. We have two top gun winners at our club and & the guys are used to looking at there stuff i guess!! I have not looped mine yet, but do rolls all the time. It spins very well also. Enjoy talking w you.....Gene
09-18-2010, 09:04 AM
#40
RE: 89
I well post some prep work pictureson the PT-19 getting ready for thefabric covering very soon. After glassing the fuselage top and tail section it was sanded smooth and sprayed with gray filler primer, sanded lightly andany uneven sections were filled with auto featheringpaste and than primed again,, I taped off the area on the balsa which well contact the covering..
1/16" wide tape as well as some plastic strips cut from styrene sheets from the hobby store were used for panels and a syrenge was used to add some revit details with white canopy glue before painting, if I mess some photos I well get them up latter and give more explanations, thanks for following,, In the first two pictures you can see I have three Great Planes 4/40" 48" pushrod tubes cut to lenght and anchored for the controls inside the fuselage.. George / aka rcwarbirdbuilder
1/16" wide tape as well as some plastic strips cut from styrene sheets from the hobby store were used for panels and a syrenge was used to add some revit details with white canopy glue before painting, if I mess some photos I well get them up latter and give more explanations, thanks for following,, In the first two pictures you can see I have three Great Planes 4/40" 48" pushrod tubes cut to lenght and anchored for the controls inside the fuselage.. George / aka rcwarbirdbuilder
09-18-2010, 10:08 AM
#42
RE: 89
Paul, I am going to have minimun 3/8"-1/2" margin for the overlap on the fabric to stick on the fuselage. I looked at some full scale PT-19 and it looks like the fabric is attached to the frame than the the top area which is metal or plywood is screwed over the fabric overlap,
What I am going to do is attach the fabric to the open area of the fuselage with at least 3/8" wide contact to the fuselage, and than use styrene strips about 3/8" wide which well go over the seam where the fuselage hard part on the top meets the fabric on the sides,, the strips well be ca+ over the seams and#4 screw well be added every couple inches to secure the strip to the fuselage, I think this well be inline in appearance and in function to thefull size craftand hold the fabric tight to the airplane.
What I am going to do is attach the fabric to the open area of the fuselage with at least 3/8" wide contact to the fuselage, and than use styrene strips about 3/8" wide which well go over the seam where the fuselage hard part on the top meets the fabric on the sides,, the strips well be ca+ over the seams and#4 screw well be added every couple inches to secure the strip to the fuselage, I think this well be inline in appearance and in function to thefull size craftand hold the fabric tight to the airplane.
09-18-2010, 11:31 AM
#43
RE: 89
Looking really good! Man, you move along fast, but makes following this thread something to look foreward to every day.Sounds like you have a plan to attach the fabric. Are you going to do your paint in the silver scheme or the blue & yellow? Keep up the good work.....Gene
09-18-2010, 01:47 PM
#45
RE: 89
Honestly, that would be my vote. It will distinguish it more than the blue & yellow ones that most of the arf manufacturers use. Sounds good! At the rate your going i expect to see it in paint soon....
Gene
Gene
09-18-2010, 03:40 PM
#46
RE: 89
I just returned from a local yearly full scale air show. Here are some pictures of a beautiful Chipmunk that was there. I should have taken more pictures, but my batteries were running low. PT-19 pics to follow next.
Regards, Richard
Regards, Richard
09-18-2010, 03:44 PM
#47
RE: 89
I just returned from a local yearly full scale air show. Here are some pictures of a beautiful PT-19 that was there. I should have taken more pictures, but my batteries were running low.
Regards, Richard
Regards, Richard
09-18-2010, 04:54 PM
#48
RE: 89
Richard thanks for posting the pictures, some very nice details can be picked from them, I was not sure if all the PT-19 wing near the main gears had the seam strap around it... Iam still not sure but this one has it,, As far as I know all the AT-6 aircraft has it, George.
09-18-2010, 07:04 PM
#50
RE: 89
Spaceworm, were they selling rides in the PT-19? We had our yearly breakfast fly in at the local airport ( practically accross the street) today also. We had AT-6s , a B-25, & a Stearman flying over the house today, amongst others. I never have seen a PT-19 up close before....Gene Definately different markings on the chippy too!
George, your Chipmunk looks GREAT in silver. I have never done a model in silver & i think its about time!.....Gene
George, your Chipmunk looks GREAT in silver. I have never done a model in silver & i think its about time!.....Gene