William Robison

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Larry:

Looking at your picture the only thing I see that might be wrong is the tail blocks. Am I wrong? Regardless, doesn't look like a major problem.

The wrinkle is what I was talking about when I said be sure both plies are smooth on the mold when you tie them down for the glue to dry. And if you only break one or screw up two while learning, the skill is well worth while learning. Many applications for this method, all the way up to forming a complete wing or fuselage.

And remember, after the first hatch skin is done you still have three more to do.

Bill.

lslewis

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[>:]Your correct it is the tail blocks. They were built out of 3/8 balsa and weigh 0.5 oz. I may try to build them lighter but there is not a lot to be gained.

lslewis

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If you remember I ordered the wrong retracts (I ordered the retracts for the VQ model of the A-26). I waited until Spring Air sent me the ones for the Wing Mfg A-26 to make the layout on the firewalls and install blind nuts to be used later if. They arrived early this week Thank You Spring Air.

I have changed the plan, I am going to install the retracts while the nacelles and the fuse has easy access. I have already drilled the holes and dry fitted the fixed gear, so installation later if necessary will be easier than trying to add the retracts.

The access for the retractable LG will need to be much larger than I realized so building a hatch is not realistic. I will make the decision of how to finish the nacelles after I install the LG and see how it fits. Currently I am re-building the tail pieces that I had installed upside down. Caution: Building of the nacelles is done upside down before you add firewalls and the end pieces be sure you know which way is up!

lslewis

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Now that I have decided to put the retracts in I did a dry fit check. The retract instructions advise "cut away to clear tire" and "cut bottom out for gear clearance. Cutting away to clear the tire was easy. Now I need to build a bottom (from the firewall to the tail) I have not figured out how I am going to to that.

Ideas, hints and suggestions appreciated.

nchrome

Islewis on your air lines be sure to get a set of airline restrictors from Robart. These will help your plane survive the slamming up and down of your gear. Will also help in the scale raising and lowering of the gear. Trust me these will work better than any wheel callor you can get plus more control of the gear. As far as the bottoms of the nussel start planking from one side to the other. Before you start though round out the back of the nussel round out and then start planking. After planking thick CA accross the planks on the inside then cut out for the gear doors then hinge. Use a small cable or dental floss accross the opening between the doors ( thread is attached to the doors not the nussel)when the gear goes up the doors will close. Make a small spring that will force te doors open. Works real good

lslewis

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Thank you nchrome, missed your advise. I have added a set of Robart restrictors to my Tower order. I will start the planking today. I had not planned on doors but you make it sound so easy.

The 7th Chadwick

lslewis

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Happy New Year!

Progress has been made. I planked the nacelles and cut out for the LG. Installed the retracts and found I had to cut even more. Installed the speed controllers, switches and an arming plug. Sanded, mated the cowling's and found I had to bend the exhaust flaps out and away. Used the heat gun. Caution a second too much heat and you have melted plastic instead of exhaust flaps. Pulled the cowling's off and sanded them in prep of painting. No picture today, nothing to show as the nacelles are dissambled.

nchrome

Did you mount the aircooler flaps like the plans say if you did then all you have to do to increase airflow is sand the nacelles until you it is wide enough to pass enough air to cool the engine. Of course if you spilt the seam between each flap then they would bend easier without heat. I personally cut each free from the backplate then used baydoor hinges and moved to where I wanted them the just a touch of CA. And wala you have a more scale looking aircooler flap plus it is opend a lot more for air circulation. Just my 0.02 worth. Be sure to fuel proof the blocks for the flaps.

lslewis

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I followed the plans and double checked them yesterday, the nacelles fit the cowlings OK but the forward hatch doesn't. That is why
I cut the exhaust flaps and heated them to fold out just to get the hatch to fit. I will install the forward vent as in the real aircraft. I plan to use a large serving size plastic spoon cut off for the air scoop, it will not be scale but it will look OK many will never know. Actually it will be more scale than the kit, which does not have the vent. I have cut a 2 1/2 inch hole in the firewall to let air pass thru. Remember this A-26 will use electric motors. The motor mounts to the cowling, not the fire wall.

I have been bashing balsa for what seems weeks now and can not see the results. So I covered one of the nacelles. It may be to early but I just had to see... The 7th Chadwick is going to be black, glossy black and it is going to be an eye full. But will this pilot be able to see her?

nchrome

Starting to look pretty good to me. A friend of mine also has an A-26 and his is black not realy to bad to keep orientated. Just make sure what you want to do and what your hands do corespond with each other. Like I said earlier mine is chrome and I don't have any problem with her. Just think about what you are going to do and do it and ignore the other planes around you. Keep the building updated for us to see and hope we all can help. Sure would like to see yours down at Taylors Mo. Labor Day Fun fly I'll be there for sure and maybe I'll Have my B-25 back together again.

lslewis

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Can't find Taylors, MO, how about SC or TN?

With epoxy everywhere I glued the wing halfs together then added the nacelles. I covered the bottom side of the outboard wing panels so I can hook up and test the servos. Sure enough one is back-wards, darn. Most of Monday was spent hooking up all the wiring. Two (2) Aileron Servos, 2 Flap Servos, two throttles. The ESC throttles will tie together with a Y cable in Phase A, if that does not work or the motors are too far out of sync Phase B calls for independently adjustable motor speeds. That is a whole new ball game.

In the first picture my wife Maria is squinting because the sun is in her eyes. Oops, I hope that is the reason. The second shot is of the wiring mess.

lslewis

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The electrical wiring is complete and the wing joint has been fiberglassed. I installed the nose wheel retract but not without complication I had already installed small shelfs for batteries leaving what I thought would be enough room for the retract/wheel etc. But I neglected to consider the nose wheel steering control horn.

I totaled up all the weights and at 9.13 lbs (total with everything) I am 8 oz below budget! The calculations say The 7th Chadwick will do well.

I have painted and trimmed both cowlings and they look good! I am going to hold off on the pictures just for suspense.

lslewis

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The retracts are history! Not one reason, lots of reasons and they add up to the last straw... The nose wheel would not retract all the way, the retract was mounted too low. Also the coil spring interferes, the batteries interfere, the control horn interferes. I do not like the large retract holes in the nacelles, nor in the Fuse. They need wheel well doors to look good. More work.

All of these problems can be solved but not now and not by this old pilot. With 20-20 hindsight I should have planned the retract installation more carefully. Next time. The photo below is to give you a hint of the mess in the nose wheel well.

desmobob

Islewis,

I've been following your A-26 thread with interest as I have a Wing A-26 kit in the shop. I've been holding off on starting it as I still have a lot of questions. I had already decided to skip the retracts as this model will be my first foam wing and first twin and I thought that's already too many "firsts." Judging by your experiences, it was a lucky decision.

Thanks for taking the time to post your progress. I appreciate it and look forward to reading more.

Good luck with your airplane,
Bob Scott
Whitehall, NY

lslewis

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Thank you for your appreciation. It is pilots like you that make the extra time to do this thread worthwhile. You have made a good decision, leaving out the retracts. Not only does it simplify the build it reduces the wing loading, important for new pilots. I add for others to check the vertical location of the nose wheel retract. I am not sure it is correctly located.

Be sure and read the Twins section of the forum, there is a lot of good information re: Twins. Check threads by "Twinman"

stefanP

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Larry I'm reading this articale and wondering did you figure ",YOUR WATTS PER LBS?" Twin endoplasum motor's even with gear boxes seem to be underpowered.You say 9lbs R.T.F. well this tells me you'll need at least 1500watts of power(9lbsX60watts per lbs) and this is on the very low side of power requirement.I've seen this plane and the wing area isn't all that big.One other thing I'd do is a static thrust test and check your watt output along with the amp draw.Your doing a nice job so far and you want to have the assurance the plane will fly when you go to the feild.Good luck,stefanP

lslewis

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StefanP,
I too am worried about being able to fly this plane with the power I have installed. I worked the data with Motocalc and it thinks it will work. As far as watts per pound at 9 lbs X 50lbs = 450 watts. 9lbs X 60 = 540 watts. I am expecting to have over 600 watts. The plane is too heavy to do really well as electric, but it is a challenge. Best yet it will be a challenge to get it flying with the low cost system I plan to use. The Endoplasmas are turning so fast, 34,000 rpm I worry about them over heating and throwing all of the solder out.

I have some aluminum fins that fit the Endoplasma designed to act as a motor mount and to provide additional cooling. I hope that will help.

stefanP

My Feedback: (2)

Larry sorry for my math mistake[]. I can tell you rite now that 50watts per lbs will not work.I stay away from the calc programs.I use three tools,Calculator,Astro watt meter,&a fishing scale.Now for thrust requirements I've read some say 1/3 of models r.t.f. weight and others 1/2.I fall stightly in the middle of these two when I do a pull test.As for your plane ,if you can get 4lbs static thrust you'll be okay.Anything less,I'd stay home.As for other power systems,you could look for two astro25 geard motors.I have seen them used at reasonable prices.If you stick to your plan and ran a paralle system you'd pull 360 watts per side with 10cell battery packs(12vX30amps) =720 total which in turn comes out to 72watts per lbs.Also you can up your amp draw to34amps you'll be in at 400watts a side.These motors are rated at35amps max but I push my AF40 G motor 36 to 37 amp static and haven't seen a problem.I know other people may say go brushless and then you'll diffently need two of everything as you can't run two brushless motors on one speed control.Well Ihope this might help,good luck.stefanP

lslewis

My Feedback: (2)

I am expecting the Geared Endoplasma to run at 33 amps at 12 volts that is 396 watts per motor 792 watts total. The running voltage is more likely to be about 10 volts for 330 watts per side 660 total. Both are theoretically enough to fly the plane. The Endoplasma motor costs $20 and the Great Planes GD-600 gear box $13. The gear box is modified to 5:1 with a $4 gear from Gary Wright Model Products http://www.gwmp.net/

Several experts have recommended the Geared Astro 05 or 25 but at $130+ each I will try the Endoplasma. If worse comes to worse I have two small glow planes the Endos will fly for sure.

The photo shows the Endo mated with the gear box. The cooling fins are my idea and have yet to be proven. The fin must be drilled to match the cooling air vents on the motor.

stefanP

My Feedback: (2)

Well good luck and keep us in the loop on your progress(By the way I've boughten used astros for $100.00 bucks and under) stefanP

lslewis

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I installed the tops for the nacelles, cutting them (ABS Plastic) to fit the wing was a process of trial and error. I painted them earlier. Stirred up some epoxy with microballoons to make fillets. Bad idea some of the epoxy flowed in one side and out the other. So I filled the voids with Hobbylite filler and will go over that with epoxy later.

Fiberglassed (3/4 oz.) the Fuse nose. Earlier I decided that the compound curves in the nose would never look good in Monokote. So the nose will be painted. The remainder of the Fuse will be Monokote. I have used Minwax Polyurethane to bond the fiberglass because it sands easily. Will it work? I have no idea. Anybody done that?

This is my goal:

lslewis

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My last model, a GP Corsair, was covered with Solartex and painted. It looks fantastic. In an attempt to keep the weight down on the Chadwick I have elected to use Monokote and just paint the compound curves on the nose. I do not like the shrink plastic coverings, I did not before and I do not now. Please understand that I am using the Monokote Trade Name as a generic for many of the coverings.

I started on the elevator and finished the day working on the wing. I did not rush, slowly using only the iron I pushed ahead. I have managed to keep all of the uglies on the bottom. Most will not notice but I will know and I am not happy! Some where I saw an analysis of various paints and coverings vs weight. Hope I can find it again.

lslewis

My Feedback: (2)

I thought the wing was done. The nacelle tops need to be secured. One flap servo had to be reversed. Then the control horn was in the wrong position. I made a "Z" bend in the control rod, it works fine but looks like I goofed. (I did) It will have to be corrected. I will require the addition of a hardwood block in the foam aileron for mounting the horn.

I purchased some water based black spray paint to use on some of the raw interior balsa that might be exposed from time to time. I have found that it is terrible stuff. Runs under masking tape, it also releases masking tape, and it is impossible on canopies. I have also found that painting a mask is much easier said than done. Thats another thread:

http://www.rcuniverse.com/forum/E_Z_...1446212/tm.htm
i
I masked and painted the main canopy. I cleaned and masked the observation canopy that I painted with the water based spray paint. Alcohol did the trick. I will paint the main canopy tomorrow with rustolium.

I could not wait, I painted the nose 13th Bomb Squadron Red!

ianober

My Feedback: (12)

Wow, I have been out of the loop on this thread, sorry guys. I have been spending way to much time on RCSCALEBUILDER.com. Anyways, I should answer Lova1/4scales request for where I got my buildings pins. Heres the link, I got them from Hobby Lobby:
http://www.hobby-lobby.com/pins.htm
These are by far the best pins I have ever seen, you'll love them!!! I have not started my A-26 yet but if you have seen my website you'll see that it is close to the end of a job queue thats pretty long. Right now I am finishing up my Spitfire and next I will be building my T-34. This A-26 is a very tough one to build. I have already cut many former templates for it and just doing that I looked at the plans and said to myself this should be interesting!! I am looking forward to detailing it out as much as possible though. Keep at it Larry, you'll be happy with the finished project!!!! Your doin a great job so far!!

lslewis

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Welcome back inober. Love the pins, next time. For me the A-26 has been a heavy one. Apparently I build slow, spending time thinking about my next move. So I have a lot of hours in the airplane. Some of the details are not coming out to my satisfaction. Remember I have only built two planes since the 50's. So I have a lot to learn before they let me in scalemasters.

My good friend and building guru Stuka Jon reminds me not to worry, 98% of the people have no knowledge you goofed and the other 2% don't care. That works, but the remaining problem is I know it is wrong.

The plane is finally taking shape. I will post a preliminary picture soon.