I just opened my new A-26 from Wing.

Short kits are among my favorites as they allow me to choose my own woods and hardware, (which I usually end up swapping out anyway). This offering will be my very 1st twin and I'm chompin' to get started.

I've had a pair of BlueBird 45's, brand new and still in the oil paper for over 2 years just waiting for the right airframe to bolt them up to...

I unrolled the plans and immediately saw POTENTIAL for a superior flying model. I have the glass nose option and will undoubtedly install this rather than the solid cone with 6 little dowels sticking out, lol.

The nacelles are rather thin but the scale outlines are shown on the plans. Fleshing these out shouldn't prove too problematic. My primary concern is the landing gear. Flying the Invader around with 3 wires hanging down just doesn't seem right :-)

I've emailed Robart but haven't gotten a reply yet. I've searched abit but haven't found which retracts will work best on this airplane.
From the plans, it appears that 3- nose gears are in order as all 3 rotate to the rear when actuated. Since a total re-positioning of bulkheads is called for when opting for functional landing gear, this is my 1st obstacle. AND...I can't invest $250.00 in them.

Has anyone else out there built this airplane? I'd like to share the building experience!

Thanks,
PM

I have built the A-26 from Wing Mfg in the last couple of years. I made a number of changes in the plane. First, the retracts: I used Hobbico retracts in the nacelles, although they take a lot of adjustment to take the wobble out of them. I moved the struts to a position about 1/2 inch behind the CG location shown. I made a "gear plate" of 1/4" aircraft ply, as wide as the nacelle and maybe 6" long. The gear was mounted to the rear end of this plate, and a HiTec retract servo was mounted to the front, with a short pushrod directly to the gear tab. The entire plate was made to be adjusted outside of the nacelle, and then installed with screws so that it could be removed for more adjustment later if needed. Pay attention to making a left and right plate, etc. and if necessary, reverse one servo so that both gear go up at the same time (don't ask me how I know this is necessary.....)

A 1/2" dia. "rocket tube" from the LHS was built into my wing before sheeting to carry the servo leads to the fuselage, plus other items covered below.

I used an MK nose gear retract. I found myself on the horns of another dilema--the two wing retract servos joined a Y yoke which plugged into the receiver. Where to plug the nose retract? I plugged it into a 6th channel, and then mixed it to operate off the retract channel as the master channel. It works fine.

You will notice there is little room for the gas tanks in the nacelles, and even less with my gear plate. And the tank was tipped badly as well. I had planned early on to use a Perry P-30 pump on each engine, with a 16 oz. tank mounted roughly on the CG in the fuselage. Two klunk lines were used in the tank, one for each engine, and the lines ran through the rocket tube and connected to the Perry pump, which was mounted just behind the firewall and behind each engine head. A small hole was made in the side of the nacelle to access the pump adjustment screw if necessary. As you probably know, the pumps require that you tap the crankcase for the pressure line which feeds the pump. The third line on the tank was the vent and overflow line, no muffler pressure is used when using the pumps.

Although I have used eight or ten pumps in other airplanes and am familiar with them, I ran into another problem which I had not encountered before. The engines, broken in on my bench, would run only 1/2 turn open on the NV, and were extremely sensitive to the setting. Adjusting the pumps for less pressure did not help. I called Conley (now the pump mfgr) and was advised that the pumps were overpowering those "small" engines, and a return line would be necessary to carry the excess fuel not required by the carb back to the tank. A "T" fitting next to the carb was installed to bleed off the excess fuel, and that line went back to the tank. Only now I was out of tank lines, having used all three already. I found that I could heat a music wire with a torch and burn a hole in the DuBro tank, on the "step" of the tank, and install two pressure nipples there to receive the return lines. I don't need to tell you what a plumbing nightmare this is when I go to put the wing on and fly, but it now works flawlessly, and the airplane is fast, like the full scale airplane was.

Excuse the length of this epistle, but I hope I have answered some questions for you. I might add that air retracts could also be installed and perhaps with far fewer problems, but I have had good luck with mechanicals over the years so stayed with them.

Clair

Azcat,

Thanks for the feedback. I did get a price quote from a manufacturer, (not Robart) for $340.00, lol...

I'm sorry but I just CANNOT wrap my brain around installing landing gear that cost 7x what I paid for the airframe. Having matched 45's already on hand does put me somewhat ahead of the price curve but I still have a wood pack to buy, hardware and other accessories. Pneumatic landing gear may just have to be scratched and your mechanical "solution" used.

ANY PHOTOS??

I'm considering using 3 nose gears, locking the 2-"mains" so as to not steer. In this manner, I can still bulkhead mount them so as to not impact the tank area...just a thought.

Did you glass your model or use a film covering? have you ever heard of this product:

http://www.fliteskin.com/page9.html

Using this to do the wing cores and glassing the fuselage looks to be a quick way for a superior camo paint job.

Let's keep the thread going. I'm going to need alotta input, lol...

PM

I glassed the wings with .6 oz. cloth and Pacer Laminating resin (epoxy), and the fuselage and tail components with the same cloth but nitrate dope. All of this followed by Rustoleum primer, and then Formula U Olive Drab paint shot from my air compressor/guns.

I am surprised that the air retracts would be that expensive. This airplane is not that large or heavy so 60 size retracts are fine.

Clair

LOL...I agree!

I re-checked Wing's website and they state THEIR pneumatics are only $119.00! How I missed that one, I just don't know.

I fired off an email asking for more info on the system and what all is included. I guessing they are only 5/32" wires and not 3/16" but we'll see. At 10+ pounds, I'm thinking that 3/16" is the way to go..especially with the landings that I'm used to making, :-)

I'm cleaning out my CF card and will start posting photos on my construction process. I usually try to assemble everything I need prior to actually starting a project. However, this one may be different!

PM

Here is where I stand with mine (wings in back).
I went with mechanicals, have a video of the test bed I made for them, will post when I get a chance.

JF,

You efforts so far look excellent! Did you use Elmer's ProBond to laminate your cores? I'm considering using fliteskins on my wing panels. Pricey, but soooo easy to get a glass-smooth finish.

I used Elmers on my Kaos 90 wing cores with great success. Trimming the expanded foam from up between the slight gaps in my skins was different, lol...

I'm electing to use the bubble nose rather than the solid version. I'm waiting on Wing's reply to my email regarding their retracts. Mechanicals may still be in my future...

Looking at the plans, I'm wondering if notching the wing at the nacelles to allow for more tank space would significantly weaken the structure? Reinforcing this with carbon fiber or ply might make a big difference in centering the fuel tanks without having to angle them so much. I'd like to use 12oz Sullivan tanks. Their Flex tanks allow you to shove them into tight places without worry. Extending the wing spar to the outboard side of each nacelle would effectively support a notched wing, I'd imagine.
Azcat's solution of a single tank is a big temptation but I resist drilling my backplates and investing in Perry pumps. I've found that simple is usually better in my construction process. When I start to get fancy, I usually pay for it somewhere down the line, (it's usually the FLIGHT line, lol).

Looking forward to your video!

PM

I got a great reply from Dan at Wing Mfg this evening.

His retracts for the Invader look to fill the bill. Altho only 5/32 wires, the weight of the airframe should be ok with these, (altho I sure would prefer those 3/16 wires).

The price is way fair and his shims for bulkhead mounting look to be sturdy.

Here's what I'm buying:

PM

PointMagu I have one of Wings A-26-B. Yes its a bomber doors and all. Yes I did plank the naicells to make them more scale. I also have the glass nose but I didn't install retracts. The ones that Dan are showing you ar B&D retracts which I have used on several planes. They will serve you well and if you want you can drill them out to except the larger wire. I have TT42s in mine and 8oz tanks. Flys fast and for about ten to twelve minuts. Be careful when you build this bird cause the original plans the nose wheel wire is too short so make sure that the wings are level with the ground or you will have a very exciting maiden flight. Definately give you that "P" factor.[X(]

nchrome,

Nice to hear from an Invader pilot! I recognized Dan's retracts as D&B's as well. The vinyl endcaps on the cylinders are a dead give-away. I considered the drilling-out option for the 3/16 wires, too. I want to get them on-hand, look them over closely though before I make any final mods-descisions.

Once the construction is done and I'm plumbing the retracts, I'll make sure to level the airframe and measure out the nose gear. I'll make the appropriate adjustment to the axels I'm planning on using. I always leave about a 1/2" "x-tra" when cutting the wires to allow for a final leveling. I mark the wires, remove the axles and cut them flush with the knuckle then grind a flat for the set screw.
That's great advice, thanks!

I've never flown BlueBird engines but I suspect that these are proto-typical of other Chinese 2-strokes. They were purchased 20+ years ago by my Uncle and I was given them after he passed away. They're NIB with all the paperwork so I'll break them in as directed. As far as 45's go, I'm thinking that they'll most likely be average powerplants.

Did you use the stock, metal motor mounts? I'm not too sure about them. They don't look terribly robust for 45 size displacements.

I'm assembling the woods I'll need. Fortunately, I already have a nice on-hand supply of balsa and plys from Balsa USA so the blocks and assorted edge stock is about all I'm going to have to buy. Again, those Fliteskins will come later on after I recover from the retract expense, lol.

PM

I have the 5/32 gear on mine and have had no problems with it. I fly from a fairly smooth asphalt runway, however, and grass might put a little more drag on the gear. I would also suggest that you consider moving the mains much closer to the CG than the plans show, to avoid the "stick to the ground" takeoffs, requiring a lot of up elevator to rotate, which then gives you a "zoom" takeoff, not good, not scale. I know this from my old pattern plane days with trike gears, plus a fellow club member has built two of the Wing A-26s, and moved the gear up on the second one to avoid such a problem.

I set my nose gear by attaching a Robart incidence meter to the wing, and adjusting the nose strut until I had a 1 degree positive reading. A negative reading will also stick the plane to the runway. OK for landings, bad for takeoffs......

Clair

Here is the video of my retract test bed:
http://www.dietandtraining.com/RC/Gear.wmv

Then I cut it up to fit in the nacelles and nose:



There are a lot of firsts for me and this model, like how do I seal the nose so I can cover it with monokote, light wood filler? Any suggestions?

JF,

Great photos. I always use DAP Lightweight spackling compound to fill imperfections and seam lines. It dries quick, sands easily and takes paint or Monokote very well.

If you want to give your film covering an "edge", you can apply 1 or 2 coats of Balsarite to the nose, lightly sand and then apply your covering. Whatever you finally decide upon, I'd run a Topflite Woodpecker over the whole affair to resist bubbles and to allow the film to stretch tight over the compound curves.

I'm sure you've seen one but I'll toss in a photo just in case, lol...

Your retract install looks super. How about a shot of the nose gear well? I'd like to see how you mounted that gear and servo, too. I do have a question, though. The space behind the servos appears to be quite narrow and shallow. Are your wheels and axels going to fit in there without binding??? You appear to have length on each pushrod to the gear actuators that could be shortened if more room is needed. Sorry, I'm sure you've measured everthing out and probably show this on your video but I can't view it on my PC. Quicktime gives me an error type 47, bad URL, reply.

I'm encouragd by everyone's ingenuity in overcoming their challenges as I'm certain to have my share as well.

PM

I think I fixed the link, give it another try.

I will post some more pics maybe tonight.

The wheels will fit, I left the gear full length for now since I have heard about the issues with the nose gear being short. Once I get it together, I will adust the gear as nessasary.
Hope it works :-)

Good pictures of the retract plates JFranco. Similar to what I did, but I made the plates removeable so I could adjust the throws on the bench and then install them in the nacelles, and also take them back out if I ever needed to for repair or adjustment.

Maybe you ought to consider painting the nose, or even the fuselage. Glass cloth, some primer, paint the nose section and Monokote the rest if you want. I made my machine guns in the nose from 1/8" aluminum tubing, with brass tubing barrel inserts showing just a bit. Look pretty realistic.

Clair

Good idea, next time I will make them removable.

I have never glassed before, so I dont want to experiment on this one. I have an old Bridi Superfli that needs some glass work, I will give that
a first attempt. If the filler and monokote dont work, I will have to peel it off and try glassing I guess.

Any chance of seeing a pic of the guns?

Here is a pic of the tire in the nacelle. Bottom has been planked as plans show, looks horrible, will need to sand the heck out of it.

Ordering my pneumatics tomorrow. I'm getting both the shims for vertical install as well as Dan's revised rail mount modification. Once I'm into the nacelle construction, I'll decide which way to go...I like having options, lol

I just ordered 4- S3151 digital servos for this one. Never used digitals before but all my flyin' buddies swear by 'em. The retracts will be actuated by an old tried and true, S3004 as will the flaps.

I'm gonna wimp out and use fake Robart plastic gear leg covers rather than oleo struts. If it flies like I'm hoping, I can always invest in them later on.

Now I'm surfing for color schemes. I like the COIN versions with tip tanks but none of these has the glass nose. Evidently, this was a WWII-Korea version that saw mostly night-fighting action. An all over black finish isn't what I had in mind. I will use the Robart wheels with spoked covers.

The WWII models featured dual 50 cal turrets, top and bottom. Has anyone used these? Also, 3-blade props are an almost necessity with this airframe. 10x7 Mastrer Airscrews is my guess.

I'll be cutting my "kit" this week. I plan on replacing the stock firewalls with birch, aircraft grade plywood as well as the nacelle bulkeads that the gear bolts up to.

PM

Forgot to ask...what type axels you plan on using???

PM

Well Dan informs me that they are out of stock on the retracts. Maybe later this week. In the meantime, I've picked up 2 units for the engines...

42 Percent Products has the greatest little glo driver I've ever seen. Uses a single cell 1.2 volt and is way simple to hook up. Packaged clean and neat, excellent instructions and quality made. Ken Anderson is the point of contact at 42 Percent and is a true gentleman. If you see their ads on eBay, the price is $34.95 but here on RCUniverse in the marketplace, the price is WAY lower! In fact, I offered 2 for $40. and he sent me an invoice! WOW! Thanks, Ken...

If you've never used a glo driver before and want low-end reliability, (especially on a twin) then this one should be your very 1st choice.

Ok, enough advertising, lol...

The digital servos should be here any day now.

The project moves forward. Maybe I'll actually cut some wood this weekend!

PM

Ordering the LASER-CUT wood pack from this outfit in Canada:

http://welasercut.com

They offer all the cut wood pieces,(other than sticks, blocks and wing skins) for $88. + postage. I'm sold even though I have most of the
wood stock already on hand.

Here's their photo of what you get. Naturally, being a twin certain parts are duplicated so a "piece count" from the photo isn't accurate...Everything is included!

Received the S3151 Futaba digitals today. SWEET. My 1st digital servos. Seems this project is going to incorporate alot of 1st's for me, lol.


PM

My laser cut wood pack should ship Monday. I've confirmed that Wing has the D&B retracts back in stock so that call is also being made 1st of the week.

I've got "feelers" out for alternate fiberglass sheet for my wing cores. I've discovered alternate sources at better pricing but their thicknesses are greater that the .010 that Fliteskins offers. Strange that you get more material for less money...I have samples on the way so I'll be in better shape to make a buying decision once I have looked them over.

I'm using the Evolution System 100 three-blade props on my engines. They are 10.5x4, provide nice bite, slower scale speed and LOOK like the full scale props used on the COIN Invaders flown during 'Nam.

The acquisition of materials continues...

PM

You may want to check this out for your twin

http://www.rcshowcase.com/html/acces.../twinsync.html

Blade47, thanks for the link!

This looks to be a very promising prototype. I was planning on using a single servo for throttle duties but after reading the .pdf file on this device, I may opt to use dedicated servos on each.

Let's see... $47 for the kit-$119 for the retracts-$88 for the wood pack-$100 for the epoxy sheets for the wing cores....the list goes on, and on, lol

I've found since re-entering the hobby that if you've got a hundred bux to spend, someone out there has just the device to make the experience more pleasant, :-)


Please keep the suggestions coming! I may not use 'em all,(I live paycheck to paycheck) but it's great having options...

PM

The unit has a very GOOD support thread

http://www.rcuniverse.com/forum/m_47...tm.htm#4700596

and has lot of posts from users that have had good success

worth the time to read

good luck with your build

You A-26 builders ought to look into Squadron/Signal Publications booklet 1134 for the A-26 Invader. Lots of pictures of the full-scale aircraft, full-scale color schemes, and history and coverage of the various models of this aircraft. Some of the close-up photos were invalueable in shaping fillets around the nacelles, the shape of the rear end of the nacelles, etc. It is well worth the $10-12 that I paid for the booklet. Got it at the LHS.

Clair