A-10 Project
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RE: A-10 Project
Hi Doug: My formers were pretty close but I just found out that building the stub wing as per plans will make it so you can only swing 7 inch props or they will hit the wing trailing edge. I found this out after epoxying the "stub wing" in place too. Rats, mice, etc. I will not tear it back out and do another stub wing but make sure when you build yours you measure the prop clearance at the wing t.e. AND the fuse. I may just try to cut down some 8X6 props or try to cut down a couple of 7X6's 3 bladed props. I'll hook up a scale to the airplane and see what gives me the most pull. If all else fails I'll cut a coupld of 1 inch ditches in the t.e's and spin the 8 inchers. There is more than one way to get this airplane done. I don't have a digital camera but will see if I can't borrow one to post a photo or two. I'm nearly ready to cover the model and only have to finish one more engine nacelle and paint them and the stub wing and then can start to cover it. I gotta admit it does make a cool looking model airplane. The wing on mine turned out really nice and light. I used one servo and bellcranks for the ailerons. Thanks for the reply and good luck on yours. I'm retired so have time to keep working on mine a little daily and that way I don't have to review what I have done before I start work on it again. Have a good one! Ron
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RE: A-10 Project
Hi Again: Yesterday, a pal of mine came over to my workshop and took the attached photos of my A-10 and several of my fellow club memebers. I hope the photos can be of use to anyone else who may be building a similar model.
Ron
Ron
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RE: A-10 Project
Looks good Ron. I see what you mean about the trailing edge being too long. Maybe you could ues a smaller diameter 3 bladed prop? I'm fitting mine with fans so thats one headeache I can skip. My problem with the engines is finding a short pipe for the 7.5's.
Doug
Doug
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RE: A-10 Project
Doug
You may want to look into a magic muffler. A magic muffler is basicly a 1/4 wave pipe with a muffler size can around it.
Ron
What about making it a pusher?
You may want to look into a magic muffler. A magic muffler is basicly a 1/4 wave pipe with a muffler size can around it.
Ron
What about making it a pusher?
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RE: A-10 Project
Thank you. After much thought I have decided to remove the stub wing and build anouther one that is about 1 and 1/4 inch longer per side and with a steeper angle on it to move the props up and out enough to clear the fuse and wing with 9 inch standard props. It'll be a couple of days of extra work and a lot of extra sawdust but that way I will be able to use conventional props that will properly use the engine power. It won't look truly scale but that is OK with me as long as the airplane can operate satisfactorily. Just watch those plans because when I built this stub wing exactly as per the plans I ended up with prop clearance problems and an airplane that would look good hanging from the ceiling but wouldn't perform satisfactorily at the flying field. I checked and double checked everything on the plans but the stub wing angle and found to my dismay it was not right for a properly performing airplane. Meanwhile, I've gotta go back into the shop and make some more sawdust while tearing out the stub wing. [&o]
#33
RE: A-10 Project
Hi Doug,
Just a note to you and others reading your thread regarding the Miller plans. While you started with the wings, I started with the tail. I had to recut three fin ribs that are drawn wrong on the plans. Also, the main spar in the horizontal stabilizer is drawn twice, once as a pattern and once within the stab. I initially cut from the stab and found it was wrong. I had to recut it from the pattern, which I guess I should have done in the first place. However, given that the stab is perfectly straight, there should have been no difference. When it comes to the fueselage sides, you absolutely must cut from the pattern as the drawing of the finished plane seems to take curvature into account, as it should.
So far, the fuselage sides, bottom and formers seem to match very well. I'll be assembling them soon. I did run into a problem with the sidewall cutouts for the stab, though. There's no wood left above the stab, which effectively cuts off the last few inches of the fuselage sides. I added some wood back above where the cutouts will be, which I'll carve down later after it's all assembled.
I still plan to build up the wings, but I guess we'll see if I can manage it. As you've discovered, the Miller plans leave a bit to be desired. If this plane ever gets kitted, as has been said, I hope they fix these glitches.
Keep up the good work.
Paul
Major edit! I thought I had this wrong as I wrote it. The pattern for the main spar of the horizontal stabilizer is drawn wrong. I cut from the pattern then matched it up to the plan of the stab with ribs. It was too short and the rib placement didn't line up. I recut the spar from the plan.
Just a note to you and others reading your thread regarding the Miller plans. While you started with the wings, I started with the tail. I had to recut three fin ribs that are drawn wrong on the plans. Also, the main spar in the horizontal stabilizer is drawn twice, once as a pattern and once within the stab. I initially cut from the stab and found it was wrong. I had to recut it from the pattern, which I guess I should have done in the first place. However, given that the stab is perfectly straight, there should have been no difference. When it comes to the fueselage sides, you absolutely must cut from the pattern as the drawing of the finished plane seems to take curvature into account, as it should.
So far, the fuselage sides, bottom and formers seem to match very well. I'll be assembling them soon. I did run into a problem with the sidewall cutouts for the stab, though. There's no wood left above the stab, which effectively cuts off the last few inches of the fuselage sides. I added some wood back above where the cutouts will be, which I'll carve down later after it's all assembled.
I still plan to build up the wings, but I guess we'll see if I can manage it. As you've discovered, the Miller plans leave a bit to be desired. If this plane ever gets kitted, as has been said, I hope they fix these glitches.
Keep up the good work.
Paul
Major edit! I thought I had this wrong as I wrote it. The pattern for the main spar of the horizontal stabilizer is drawn wrong. I cut from the pattern then matched it up to the plan of the stab with ribs. It was too short and the rib placement didn't line up. I recut the spar from the plan.
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RE: A-10 Project
Making the templates for the fuse sides and bottom.
See-Temp is great stuff. Just lay it over the plans and score it with an X-acto knife and it tears clean alone the score line. Very easy. Note the glued up 1/4" balsa boards in the background which will be the fuse sides.
See-Temp is great stuff. Just lay it over the plans and score it with an X-acto knife and it tears clean alone the score line. Very easy. Note the glued up 1/4" balsa boards in the background which will be the fuse sides.
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RE: A-10 Project
Thanks Rich. I'm trying. Just wish I had more time to spend on it.
Here we have the front bulkheads installed on the left fuse side. Paul had some problems getting the 1/4" balsa sides and bottom to curve at the front so I added some kurf cuts. Hopefully this and some water will do the trick when the time comes.
Here we have the front bulkheads installed on the left fuse side. Paul had some problems getting the 1/4" balsa sides and bottom to curve at the front so I added some kurf cuts. Hopefully this and some water will do the trick when the time comes.
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RE: A-10 Project
Hi: Your A-10 is really looking nice! I have mine half covered and sat it on the gear yesterday and discovered that I have to add 7 ounces of lead on the nose just to keep it from sitting back on its tail cone. I'll be interested to see how much total weight I will have to add to balance it on the CG after I get the engine nacelles painted and everything in place on it. Since mine is a lot smaller model than yours and I can only fit 4 ounce tanks (as per the plans) in it, I'm wondering what size fuel tanks you will be using with those ducted fan engines. Thanks for posting the "progress" photos - its really looking GOOD![8D]
Ron
Ron
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RE: A-10 Project
Ron,
Glad to hear your project was nearing completion. Wish mine was. I'm enjoying building it though.
What did you end up doing about your prop hitting the wing problem?
I'm hope to place 2 16 oz tanks over the CG and pumping the fuel up to the engines. I'm doubtful at this point that they will fit in the fuse so I will probably end up the 2 12 oz. We'll see.
Doug
Glad to hear your project was nearing completion. Wish mine was. I'm enjoying building it though.
What did you end up doing about your prop hitting the wing problem?
I'm hope to place 2 16 oz tanks over the CG and pumping the fuel up to the engines. I'm doubtful at this point that they will fit in the fuse so I will probably end up the 2 12 oz. We'll see.
Doug
#46
RE: A-10 Project
Hi,
I too am building the Keith Spark A-10. I have a posting with similar title elsewhere in this forum. I asked him about the prop clearance as it was apparent to me after studying the plans and reading his article that nothing standard would fit.
also another guy from the club got two flights out of his standard built plane - JUST TWO. It would not get off the ground due to all the thrust lost to shortening the prop and increasing the pitch!
Anyway, in corresponding with Keith Sparks he had the attached e-mails of "frequently asked questions". He agrees that what Rocky is doing will do the trick - though in his article he swears by the three blades trimmed back.
I contacted Grish products - they specialize in non-standard props and they agreed that this was a problem and I didn't like their answer about getting a lower displacement engine. Particularly when i saw the guys plane not take off with a .25
So WHEN I get around to working on the project again I may do what rocky is doing or go with a pusher that someone else suggested. Though I scratch built a pusher jet and it overheats all the time.
I attached the two messages for you guys to look at.
Keep us informed of your progress.
Good luck,
Sina
I too am building the Keith Spark A-10. I have a posting with similar title elsewhere in this forum. I asked him about the prop clearance as it was apparent to me after studying the plans and reading his article that nothing standard would fit.
also another guy from the club got two flights out of his standard built plane - JUST TWO. It would not get off the ground due to all the thrust lost to shortening the prop and increasing the pitch!
Anyway, in corresponding with Keith Sparks he had the attached e-mails of "frequently asked questions". He agrees that what Rocky is doing will do the trick - though in his article he swears by the three blades trimmed back.
I contacted Grish products - they specialize in non-standard props and they agreed that this was a problem and I didn't like their answer about getting a lower displacement engine. Particularly when i saw the guys plane not take off with a .25
So WHEN I get around to working on the project again I may do what rocky is doing or go with a pusher that someone else suggested. Though I scratch built a pusher jet and it overheats all the time.
I attached the two messages for you guys to look at.
Keep us informed of your progress.
Good luck,
Sina
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RE: A-10 Project
Doug: I just built an whole new stub wing. It gives me 3/8ths of an inch clearance between the fuselage and the wing T.E. That way I can swing the 9 inch props the Fp .25's like. Are you using fuel pumps on your engines or relying on muffle pressure to get the fuel to the carbs? I'm going to try the muffle pressure route.