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-   -   The Scratch Plane featured in Fly Rc (https://www.rcuniverse.com/forum/scratch-building-aircraft-design-3d-cad-174/7250867-scratch-plane-featured-fly-rc.html)

jg95762 04-09-2008 12:28 AM

RE: The Scratch Plane featured in Fly Rc
1 Attachment(s)
The second wing went together much more quickly, partly because I discover the razor plane for shaping the 1/4 leading edge!

Here are some pictures of my partially complete fuselage. It took longer than I expected to glue the 1/64 ply and 3/32 wing supports and then sand the wing support to shape. I could certainly do it faster next time.

To make sure the wings sit correctly in the fuselage I ended up drawing some lines on the plan to see that a line through the two holes in the ribs should be parallel with the top line of the fuselage extended. I then drew a line on the ribs and a line of the fuse and carefully sanded until I could get the wing to fit in with these lines parallel. I am not sure how critical this is, but it obviously effects the angle of attack.

I then extended the lines on the plans that show where the formers go so that I could put the fuselage halfs on the plan an mark where the formers go.

It was a little tricky gluing it all together. I cracked on of the formers because the CA set so quickly and I didn't have the former square. But some additional CA fixed that! I managed to round off the top of the fuselage where the horizontal tail feather goes but fixed it but glue on some 1/16 balsa and sanding it down.

Tonight I put most of the skin on the fuse and am happy to see that it is square and seems strong.

Anyway, so far no major screw ups. At least not that I am aware of.

I was trying to figure out how to glue the 1/4 wing tips to the wings but wasn't sure how best to do it. Has anyone done this yet?

When it comes to putting on the monocote or whatever the covering is I am clueless - are there any good forums that someone can point me at?

lrglnman 04-09-2008 04:20 AM

RE: The Scratch Plane featured in Fly Rc
Jg I got my wing tips glued on monday. all you have to do is center the leading edge and trailing edge with your tips and glue with thin ca. after it is glued in place , come in at the main spar and glue in some wing tip angle bracing on top and bottom. thats it! my wing looks real nice . the razor plane make easy work of the leading edge. also a balsa strip cutter is real nice as well.

jg95762 04-09-2008 02:55 PM

RE: The Scratch Plane featured in Fly Rc
When you say wing tip angle bracing is this a piece of triangular shaped balsa or something special? If balsa, what dimension (1/4, 1/8, 1/16) did you use? Any photos??

I have a balsa strip cutter - it is great tool. I also had the razor plane when I built the first wing but was too dumb to think to use it!

lrglnman 04-09-2008 07:57 PM

RE: The Scratch Plane featured in Fly Rc
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I hope this drawing will help. I will post pics as soon as I can.

lrglnman 04-09-2008 07:59 PM

RE: The Scratch Plane featured in Fly Rc
well It did not turn out like it was suppose to. Sorry. As soon as our club photographer sends me the photos I will post them here.

jg95762 04-09-2008 11:32 PM

RE: The Scratch Plane featured in Fly Rc
Thanks - Your drawing is plenty good enough for me to see what you did. I will add the same type of 1/4 inch wing braces in line with the spars, top and bottom. They make a lot of sense and I am surprised they were not called for on the original plan.

I epoxied my two wing halfs together tonight - took quite a while to get set up to glue them, but I am hopeful they will come out straight! If they don't I wont be happy.

I found a good series of videos on how to apply ultracote - http://www.rcuniverse.com/magazine/a...article_id=726
Now I need to go buy and iron and heat gun. Any recommendations on what to get? Also is there particular covering material that I should use or not use?

lrglnman 04-10-2008 06:03 AM

RE: The Scratch Plane featured in Fly Rc
This is the set up I use not too expensive. I like this one better http://www3.towerhobbies.com/cgi-bin...?&I=LXB361&P=0
Ultracoat is the easiest to use any of that will do fine. one thing though make sure you drill a small hole in each rib so hot air can escape as you install the covering. 1/8" hole will work fine. The trick to ultracoat is getting the iron hot enough to lay down the covering but minimize the shrinkage . Then come back with the iron hotter and shrink the covering. Any trouble spots hit with the heat gun. thats my method of doing it. work slow , take your time.

cdnarcher 04-10-2008 08:58 AM

RE: The Scratch Plane featured in Fly Rc
I just picked up the rag yesterday and got the plans resized. I will start on it next week. Should be fun.

jg95762 04-14-2008 02:50 PM

RE: The Scratch Plane featured in Fly Rc
huh - it looks like there were some server issues over the weekend and some entries were lost. I will repost the pictures that I added Friday night.

One of the questions I had was about the Trailing Edge, which is a fair bit deeper than the 1/4 deep aileron stock that I purchased per the plan. I am not sure if this is because I messed up or what. Anyway, I can glue some sheeting on to the bottom of the airleron to make it the same depth/thickness as the trailing edge, but I am not sure if this will change the flight characteristics???

jg95762 04-20-2008 12:09 PM

RE: The Scratch Plane featured in Fly Rc
1 Attachment(s)
Here are some pictures from a week or so ago that show how I glued to two wing halfs together. I used two 1/4 inch pieces of wood under the outer ribs, then used a big clamp that I built from a home depot yard stick. I put packing tape on the underneath of the wing halves before putting the epoxy on. I then put packing tape over the top of the wing and put a one-by-four on top of the whole thing to keep pressure on it while it dried. The result was good. I also put the nylon bolt through the wing into two pieces of 1/4 ply. I used a metal bolt of the same size with a notch in it to cut the thread and then ran thin-CA down the thread of the metal bolt and screwed it in and out to make the thread hard. Once I got the wing on with the dowel and the bolt there was small (1/16) gap under the wing. I guess this is due to the dihedral. Anyway, the last picture shows how I glued some 1/16 sheeting on to 'fill' this gap.

larrypaul 04-25-2008 09:33 AM

RE: The Scratch Plane featured in Fly Rc
Finished my scratch, right after I got the magazine, built it with lighter materials, such as changing sizes in fuse sides and and fillers,also added landing gear, and this model does fly great, :Dfully airobatic as well, built a lot of models but the scratch is #1 now, monokote covering, and a cf2812 Emax, with 7x6 prop:)

larrypaul 04-25-2008 09:35 AM

RE: The Scratch Plane featured in Fly Rc
11 volt 1000 ma battery supplys the power LiPo[&:]

larrypaul 04-25-2008 09:37 AM

RE: The Scratch Plane featured in Fly Rc
Great simple club project!!!!!!!![>:]

Flash1940 04-25-2008 10:11 AM

RE: The Scratch Plane featured in Fly Rc
I wouldn't wish to bust anybody's bubble....but it looks to me as though there's a lot of space between ribs.....too wide for me anyway. Wide rib spacing causes excessive covering sag between ribs. Maybe I'm off base here....but if it were me.... I'd probably stick a half rib in between each of them....


carlosponti 04-25-2008 11:17 AM

RE: The Scratch Plane featured in Fly Rc
flash in the article the covering doesnt sag at all between those sections because of the sheeting on the d-tube and the rib caps and the trailing edge sheeting.

ps i kept article for these plans so i may build them sometime in the future looks like a cool sporty kind of plane.

jg95762 05-04-2008 01:48 PM

RE: The Scratch Plane featured in Fly Rc
1 Attachment(s)
Here are some more photos. In the first one I was trying to see if the C of G was anywhere close. With the 1320mah battery as far forward as I can get it the C of G is pretty close. The thing I had the most issue with was getting aileron linkages set up - next time it will be easier.

The plane is now complete, but I am currently too chicken to fly it! It is fairly windy here so I will probably wait till next weekend.

Has anyone finished there plane and flown?

jg95762 05-04-2008 01:50 PM

RE: The Scratch Plane featured in Fly Rc

Larrypaul - why did you go with the 7x6 prop? Also, do you have pictures of the landing gear?

jg95762 05-17-2008 12:31 PM

RE: The Scratch Plane featured in Fly Rc
I flew my Scratch for the first time this morning and it flew extremely well. When I hand launched it I was expecting it to go straight out and maybe even drop the nose, but instead it went straight up at a 45 degree angle! Needed hardly any trim. Glides really well, and is really fun to fly - considerably more agile than my T28. The landing was good; no damage! I am really stoked at this point - my first scratch built not only flies but flies really well. I think I am really hooked on scratch building!

lrglnman 05-17-2008 07:20 PM

RE: The Scratch Plane featured in Fly Rc
Thats great JG!
Since I got this thread started I have all but stalled my project build[:o] I have a wing built and built a fusealage but I mess it up and so I will start another Monday nite. Several guys in our club has built one and flew theirs . They said it needed a bit of down thrust and move the cg back a bit. I flew one and it flew great.

lrglnman 09-20-2008 11:38 PM

RE: The Scratch Plane featured in Fly Rc
1 Attachment(s)
Well I finally got her done this evening. I will test tomorrow afternoon after I do alot of praying. Its been along time and due to some health probs I go her done!! The pic does not do her justice . will post an update asap.

jg95762 09-28-2008 09:23 PM

RE: The Scratch Plane featured in Fly Rc
Hey Lineman, Glad to hear you finally finished her! She looks great. Did you fly her yet??

lrglnman 09-28-2008 09:40 PM

RE: The Scratch Plane featured in Fly Rc
Well, got several flights in her and it is a real fun plane. I am running the Atlas 2312/26 from Hobby Lobby with a E -Fight 20 amp speed control and a 2100 mah battery from FMA Direct, Cell Pro brand. HS55's all around and a 9-6 APC prop. Has good vertical but not unlimited. It will scoot with wide open throttle. I think it's a keeper. The only thing is you got to be careful with the prop on landing or it will break off. a prop saver is a must. or set the break on the speed control and watch the direction of the prop on landing. i made the wing in one piece and installed 2 servos in the wing. I hate torque rods. I work just 3 min from our field so this plane is going to stay in my office so I can run to the field on lunch to vent some steam. :D

jg95762 09-29-2008 08:20 PM

RE: The Scratch Plane featured in Fly Rc
Great to hear that it went so well.

I have a Hacker 20-22L, Eflite 25A. Originally I had a TP 1320mah but I think I was running to close to 100% of the max C rating and only got about 50 cycles out of it. I now have a couple of different 2100mah (Thunder Power and First Flight I think) and a Parkzone 1800mah. All three of these batteries move the CofG forward about an inch but it still flies well. The prop is a 9x7.5 SF and I have broken two or three over the 100 or so flights in the last 4 months. I have the ESC brake on but I am landing in weeds or hard dirt which is not very forgiving. I have tried a 10x4.7 and that definitely generates more lift with less top speed. With over 100 flights I have only crashed badly once, but had quite a few close calls. When I crashed a big cloud of dust came up and I was sure the plane toast. Fortunately it hit straight on and did not cart wheel. The firewall pushed out, and the wing pushed the former out and the nylon bolt broke as it was supposed to. It took about 3 - 4 hours to rebuild and it is a good as new - the 1/64 ply doublers really saved the fuselage.

I have actually built a second plane to the point of covering but haven't finished it - I really like the wood working part but dislike putting the ultracoat on. I have a couple of different BP motors and a BP ESC ready to go. One of the motors is quite a bit more powerful. I have various props to try also. The two servo thing makes sense to me - the aileron linkages are a pain to get straight, although on the second plane I did much better than the first.

I am considering putting landing gear on but haven't gotten around to it.

This is only my second RC plane and it has been a great learning exercise from both the building and flying standpoint.

I fly about five minutes from my house so I frequently disappear after dinner or on the weekend and get one or two flights in - it is a great stress relief.

lrglnman 09-29-2008 09:46 PM

RE: The Scratch Plane featured in Fly Rc
the great thing about this little plane is its easy to repair if something bad happens. so far I really like my plane. sounds like your set up is working good for you. The ultracoat is a bit intimadating but after you do a few planes it gets better. I found That i don't mind it as bad now that i have covered several planes and my skills are getting better. I had several :)good comments on my scratch my head swelled a bit.:) I am thinking of building a wing with diheadral in it just to change things up a bit.

jg95762 09-30-2008 08:27 AM

RE: The Scratch Plane featured in Fly Rc
Doesn't your wing have any dihedral? Mine has whatever the plan called for. Maybe I should build one without any dihedral to see how that flies. Have you thought about landing gear?? There seems to be no easy way to make the tail wheel steerable but I am not sure how much of an issue that is since I have not flown a tail dragger.

On a different note - I am seriously considering buying the new Eflite Pulse 25 as my first ARF and a somewhat larger, low wing plane, that is a tail dragger.

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