RC scratchbuilt Albatross in progress
 

Hi everyone. I'm scratch building a large brushless electric scale Albatross. I'm basing it off of stuff from the internet as well as an old monogram model I bought off Ebay. It will have a two piece wing, a video camera in the nose, and still camera in the aft belly. I though I would share the completed chassis and retract mechanism that I will build the fuselage around. The final wingspan will be 2.3 meters. You can see a video of it working at the following link. http://www.stef.com/Chassis.mov Now on to the wings!! (I tried to upload pictures here but I'm having problems)

[link]http://www.stef.com/Chassis.mov[/link]

RE: RC scratchbuilt Albatross in progress
 

i'm glad to see that there are other people out there doing this kind of stuff. am trying myself to do what you have done, that is an awesome plane to myself to. as soon as the temp lets me out to my workshop i myself will be doing a dc3 settup. keep going!

RE: RC scratchbuilt Albatross in progress
 

[8D]Stef,

That is one awesome retract mechanism you've designed! Simply brilliant! Can't wait to see the rest of your progress!

RE: RC scratchbuilt Albatross in progress
 

Thanks guys, I'll post more in a few weeks :) -stef

RE: RC scratchbuilt Albatross in progress
 

Hi everyone, I've made a bunch of progress.

I'm very near completion of the basic construction and then I can move on to finish work.

So far everything you see weighs 5.9 lbs or 2700 grams - so I am l on my way to meeting my target weight between 7.8 and 10.4 lbs. or 3538 and 4717 grams

Once the entire model is sheeted with 1mm balsa, I will cover everything with 3/4 ounce fiberglass.

Thanks BigR for you advice on using an elevon mixer for my differential thrust, works perfectly!

I've uploaded another progress video here:

[link]http://www.stef.com/JuneProgress.mov[/link]

I hope you enjoy it and any comments, tips, or suggestions are greatly appreciated.

Again I try to upload pics here and I keep getting an error. I will try to figure out what is up and will post pics if possible.

:) -stef

RE: RC scratchbuilt Albatross in progress
 

Okay, problem solved, here are some pics :) -stef

http://www.stef.com/Junepics/Construction.jpg
http://www.stef.com/Junepics/Wiring.jpg
http://www.stef.com/Junepics/Spinners.jpg
http://www.stef.com/Junepics/NavLights.jpg
http://www.stef.com/Junepics/DigitalCameraMount.jpg
http://www.stef.com/Junepics/Overview.jpg
http://www.stef.com/Junepics/GearDelayAdjust.jpg

RE: RC scratchbuilt Albatross in progress
 

nice. are you going to have plans available? because id be interested to build one. and those planes are awesome!

RE: RC scratchbuilt Albatross in progress
 

WOW! Very impressive, and full of tremendous ideas! [8D]

RE: RC scratchbuilt Albatross in progress
 

Thanks for the nice comments guys :) As for plans if enough people want them I would be happy to clean them up, write up some instructions, and make them available. How would you want them? As a pdf where you take it to a printer, or paper plans? I'm looking to have this thing flying early September so I could probably have plans dialed in and ready a month after that. :) -stef

RE: RC scratchbuilt Albatross in progress
 

OMG Great work! Man I hope I get that creative one day. [sm=thumbs_up.gif]



Luftwaffe Oberst
Aero Modelers Club
AMA District II
Pulaski, NY

RE: RC scratchbuilt Albatross in progress
 

Thanks :)

I've got an identical thread over at RC groups. So this update is pretty much the same as I've posted there.

So I balanced and finished my spinners and props. I printed and sealed all my waterslide decals. I've decided to do a weathered look for the whole plane. I think it looks more real and is also a lot less work than trying to make every surface and detail perfect. Even though I have a lot of building left, I went ahead and took a few pieces all the way through the finish process so I could get an idea of how much time would be involved and how much work I was willing to do. My riveting was pretty shaky but I'm sure my technique will improve. I'm going for the 5 foot read anyway. I'm very proud of my grease trails though!

I hope you enjoy the pics -stef

http://www.stef.com/Albatrosspics/up...6_07/props.jpg
http://www.stef.com/Albatrosspics/up...6_07/layup.jpg
http://www.stef.com/Albatrosspics/up...07/process.jpg
http://www.stef.com/Albatrosspics/up...lsriveting.jpg
http://www.stef.com/Albatrosspics/up...stabilizer.jpg

RE: RC scratchbuilt Albatross in progress
 

Your work is simply amazing!!! Keep it coming please!

RE: RC scratchbuilt Albatross in progress
 

Thanks again for the nice comments! :)

I am progressing rapidly now, definitely kicking it into high gear to meet my self imposed deadline. I want to finish by August 20th because that is when I go off on a family vacation. First flights, with video of course, will be the weekend of September 15th/16th. I will post the video soon after that.

Cowlings:

I resumed work on the wings, this time with the top half of the engine cowlings. I had previously molded these forms wrapping saranwrap, then 6 oz glass, then more saranwrap around my wood form. They are featherweight at this point, and will have increased strength and stiffness when bonded to the wings, firewall, and bottom half. I roughed out the depressions for the exhaust stacks, and created fillets both inside and out with expoxy and microballoons. I will smooth the transistion later, and I will add the exhaust pipes at the very end.

Fuselage:

I finished sheeting the fuselage. Some parts went more smoothly then others. There are quite a few difficult transitions. I had to redo one section near the tail as I didn't correctly anticipate the way the tail's underside flows into the rear chines - I will update my plans accordingly should anyone want to build one of these for themselves. I then began to glass the fuselage with 2oz in the forward areas and 3/4 oz in the rear. I doubled up certain areas that I know I will be doing considerable sanding and thin filling.

Wheel wells:

After crossreferencing pictures of a real albatross, I decided to make my wheel wells more realisitic by adding the rounded section you can see in the pic, and narrowing my strut flaps to a more accurate dimension.

Front hatch:

I wanted to the nose section into a large removable hatch so I can easily service the still camera, the video camera, and the front landing gear mechanism should it need servicing. I knew I would end up with a thin fiberglass shell for the hatch so I did a sloppy basket weave-like layup of stringers. I used copius amounts of bondo to finish the form, drew and masked my hatch line, used furniture wax for mold release, applied the equivalent of 3 layers of 2 oz glass, and cut and released the part when cured. The remaining shell is very light and strong, and I plan to use a snap on tongue and groove type connection to the fuselage to ensure a watertight seal.

Until next time :) -stef

http://www.stef.com/Albatrosspics/up...13_07/cowl.jpg
http://www.stef.com/Albatrosspics/up...13_07/fuse.jpg
http://www.stef.com/Albatrosspics/up...13_07/gear.jpg
http://www.stef.com/Albatrosspics/up...3_07/hatch.jpg

RE: RC scratchbuilt Albatross in progress
 

VERY NICE , brings back a lot of memories, I flew crew on one in the early 60's. ENJOY !!! RED

RE: RC scratchbuilt Albatross in progress
 

Did a couple water landing, and takes off with jeto from Friench frigate Sholes; half way from Oahu, HI to Midway Island when I was stationed out there. The model looks great! Got plans started for a Donier DO-24, a real flying boat. It takes a long time to develope those plan, good luck!

RE: RC scratchbuilt Albatross in progress
 

Hi,
Lovely job, a craftsman at work!
You mentioned glue dot rivets; are they applied individually or in rows through pierced tape (as in www.mickreevesmodels.co.uk )?

I once built a small electric powere Czech kit of the Albatros and found it floated a bit too nose down with their recommended flying CG, and so the nose tended to throw up water. It was OK once i got the nose up and the hull planing though. have you lengthened the nose at all to get more buoyancy up front?
Regards,
Alasdair

RE: RC scratchbuilt Albatross in progress
 

That is some of the best craftsmanship I have ever seen. The finish is amazing. Cant wait to see more. :)

RE: RC scratchbuilt Albatross in progress
 

Thanks all for the wonderfull comments. You are too kind! The low res pics don't show just how "hand made" this thing is!!

Alasdair - to answer your question about the rivets I'm just doing them individually with a syringe. Once I got my rythem going it took about 20 minutes per stabilizer side.

Okay, more progress!!!!

Floats:

I ruined my first float mold by mixing to hot a batch of epoxy, which then rendered my mold release ineffective. I was left with my positive form, fused to the mold!!!! You can see in the upper left pic I thought I could ressurect the positive form and remold it, but I quickly realized this was futile. The following three pics show a new form, carved from EPS foam, then a layer of expoxy and bondo to smooth everything up, and the last pic shows a latex form in progress. I plan to split the latex mold in half, then apply several thin coats of epoxy and microballons to each half. Then when things are looking strong enough I will join the two halves add the tongue that will interface with the wing. The floats will be held in place by a magnet for simplicity, though the forces will be taken by rigid walls.

http://www.stef.com/Albatrosspics/up.../floatmold.jpg

Front gear:

I decide to paint up and weather some more parts that are done. In the top left pic you can see the front and rear rims for the main wheels (the more "dirty" rims are the inside ones)
and some pieces for the hydraulics and the front wheels. I then assembled the front gear and now its ready for installation. The long thin rod you see on the front gear shaft allows castering but brings the gear back in alignment so there are now problems with retraction, in theory..... :)

http://www.stef.com/Albatrosspics/up.../frontgear.jpg

Main cabin/hatch:

I decided to use a pushrod to create what I think will be a fairly watertight seal. I built the flange to support the female portion first, then added the rod, "dremeled" and sanded it open, then added the male portion, and a flange to support it. It mates quite nicely. Its not as "snapolicious" as I had hoped, so I will have to add a couple of simple clasps. The geometry is such though that with the wing in place, the hatch will not budge - so barring some major crash it should be easy to keep the hatch on and the water out.

http://www.stef.com/Albatrosspics/up...7_07/hatch.jpg

Wings:

I finished sheeting the bottoms of the wings and added the same unidirectional carbon reinforcement that I added to the top spars. I then mated the cowlings to each wing half.

http://www.stef.com/Albatrosspics/up...gsandcowls.jpg

Wings and fuselage transition:

Using a combination of 1mm balsa and EPS foam, I feathered the transitions between the fuselage and the wing profile. I will cover these transitions with 2 layers of 2oz and be sure to do all finish work with all the pieces assembled, to preserved the smooth transitions. I added a buffer of 1mm balsa, to create 1mm gaps between the hatch and fuselage, which I can then add squishy piping or something to create a water tight seal. I'm not too worried about a little bit of water getting in because the interior space is vast, and no electronics will be on the floor of the fuselage.

http://www.stef.com/Albatrosspics/up...ndfuselage.jpg

Cowl gear flaps:

To round out my landing gear setup I had to make one last set of flaps. The geometry on these cowl flaps is a nightmare, lots of funky angles, but everything seemed to work out in the end. I use a rubber band to link them to the gear, because when I take the wings off, these flaps stay with the cowlings. There is a small quicktime movie [link=http://www.stef.com/Albatrosspics/update 7_27_07/cowlgearflap.MOV]here[/link] that shows how the cowl gear flaps work with the rest of the gear flaps.

http://www.stef.com/Albatrosspics/up...wlgearflap.jpg


Until next time :) -stef

RE: RC scratchbuilt Albatross in progress
 

Everything is VERY impressive. Please keep the pictures coming.

Jon

RE: RC scratchbuilt Albatross in progress
 

Looking good. What do you think your finished weight will be?

RE: RC scratchbuilt Albatross in progress
 

ArmedZagi I'm shooting for a finished weight of 7.8 and 10.4 lbs. or 3538 and 4717 grams, and Alasdair I did not modify the nose for bouyancy. I kept it as scale as I can make it. In fact the only thing I've conciously modified on this plane is the airfoil/chord - but planform and wing area remain scale.

RE: RC scratchbuilt Albatross in progress
 

Stef, great looking project. Have you gleened any information regarding engine thrust lines/horizontal incidences?

RE: RC scratchbuilt Albatross in progress
 

Sasquatch - nope, just pretty much eyeballing everything and using a bit of experience and intuition, then hoping for the best!!! I figure more suspense that way! I have 5 or six degrees of positive incedence between waterline and wing chord line, then I think about another 7-8 degrees based on pics between chord and thrust line. We shall see!! :) -stef

RE: RC scratchbuilt Albatross in progress
 

Stef,

Where's your "pull point" on that gear?? It almost looks like you'll need 2 servos to suck that gear up and put it down.

Chris

never mind, just watched the first video, HOLY CR*P!!!

RE: RC scratchbuilt Albatross in progress
 

Hi Chris, this movie I had made should answer your question. I guess you could call is a pull pull system with just one servo doing everything :) -stef
[link=http://www.stef.com/Chassis.mov]Chassis movie[/link]

RE: RC scratchbuilt Albatross in progress
 

love the retracts---do you have a job with Disney in the Animatronics division? You ever get some plans inked put me on the list!
!;):D

RE: RC scratchbuilt Albatross in progress
 

Hi stef,

amazing work, great details on the stabi.
Have you considered making a mold and going full composite? With all those rivets it would be a shame to get only one model from all the work :-)

Best regards
Hank

RE: RC scratchbuilt Albatross in progress
 

Thanks guys for your comments :) No animatronics job, but perhaps a watchmaker in a past life! Growing up with lots of legos helped for sure!

I have thought about making molds of the final model but there is a bit of assymetry in my fuse (I'm building this thing fast, no slowing down!!) and there are definitely things I want to update in the plans. Mold making is also such a pain in the @#$* that the final costs to the consumer I fear would be outrageous. But if there is interest, I'm interested! I figure when the plane is done, and she is put through her paces, and doesn't spiral into the drink - I'll think about everything from plans, to plans + parts, all the way to fully molded. But for now, just have to finish the plane first!!! :) -stef

RE: RC scratchbuilt Albatross in progress
 

Hey stef,

making a mold is really no big hassle with the "new" materials available. I threw together the mold for a 65" long jet fuse on a weekend.....for under $130. My guess is you can come in at under $500 for a full set of molds and not spend more than a week on them.

Taking them off a finished model will be tough though, you might need to end up building a new plug model.....but please build straight then :-)

Best regards
Hank

RE: RC scratchbuilt Albatross in progress
 

Hank - I like those numbers! My only molding experience has been with RTV, epoxy, and now latex. But a new plug would certainly be in order :)

Okay, more progress to report :)

Front Gear:

I primed, filled and sanded the forward portion of the bottom hull so I could create my front landing gear bay doors and hinges. I had to use quite a bit of filler to compensate for my sloppy planking job, but I'm happy with the weight of things thus far so I'm not too worried. [link=http://www.stef.com/Albatrosspics/update 8_3_07/frontgear.MOV]Here[/link] is a video of the front gear and flaps in operation. They are not perfectly to scale in the way they are hinged, but from a distance I think they'll pass for a likeness. The flaps are held closed by a rubber band, and pushed open by the front gear, a low tech method but simple. I forgot to think about the buoyancy of the wheels when design my landing gear setup, and so I may have to do some bathtub tests to adjust things if I want to be able to taxi from a water landing onto land and vice versa.

http://www.stef.com/Albatrosspics/up.../frontgear.jpg

Float mold:

After many layers of latex added to my new float mold, I cut it open and found things way too floppy to mold as is. I put the latex halves back over the mold and wrapped everything in fiberglass, added epoxy, and sarranwrapped everything ("poor man's vacuum bag"). I then dremeled it back open and had two halves, sufficiently rigid, but flexible enough to release the parts.

http://www.stef.com/Albatrosspics/up.../floatmold.jpg

Molding the floats:

To cast and make the hollow positive forms, I started by brushing two light coats of epoxy and micro balloons. Then I added a couple layers of 2oz fiberglass, cut in little pieces and placed on the bias. The halves were quite flexible by themselves and I had to be careful not to tear or crease the parts when taking them out of the mold. I don't have a lot of molding experience, but this latex float mold has been the least hairpulling of them all.

http://www.stef.com/Albatrosspics/up...oatmolding.jpg

Joining the floats:

I tacked the lightweight halves together with superglue, then poured a heated batch of 30 minute epoxy and microballoons through a top hole, and just rotated the mold around and around until all the seams were covered from the inside. I could see the flow of epoxy so I was able to make sure the epoxy flowed evenly. Blowing air through the top hole revealed a couple bubbles, which I then filled, lightly sucking air so the epoxy would fill the void. Each float at this point is about 75 grams.

http://www.stef.com/Albatrosspics/up...oatsjoined.jpg

Until next time :) -stef

RE: RC scratchbuilt Albatross in progress
 

Hy Stef,

I started making molds a few years back and have gotten quite some experience (both good and bad), so maybe a short intro into easy mold making (i mean durable molds for 100 parts +).

First i take a plastic sheeted piece of wood (like for bookshelves) and cut the contour of the object. The (waxed!!) object is placed into this cutout so that it protrudes exactly halfway. I tack it in place using that colored clay type of stuff the children usually play with. The seam all around is then filled with candle wax (light it and let it drip in, scratch off all the excess after it has cooled with a sharp knife).
Now drill a few holes and place steel rods in there.

Thats all the preperation.
Now you start laying up the mold. First apply a coat of mold surface resin (usually black or blueish) with a brush. Once this gets tacky, i cover everything with a thin layer of fibreglass cloth+epoxy. All the sharp corners and areas where bubbles could form are filled with epoxy goo (thickened with glass bubbles or similar)
Before it starts to cure i mix up a batch of laminating ceramic, sink the special fabric in there and just massage it onto the laid up epoxy. Walk away for 24 hours. Part 1 complete.

Now turn it around, take off the wooden plate (leave the steel rods in there!), clean it off and wax it again, and then repeat the procedure. When this side has cured, simply pull out the steel rods and pull the two haves apart.

With the rods you can always get the 2 pieces aligned just right, and you don't have to join them after taking them out of the molds. They will come out with just a very thin seam....
I buy all the stuff, especially the ceramic and the special "M1" fabric, at r&g : http://www.r-g.de/en/
I'm sure there's a supplier in the US as well. That stuff is cheap, as 1 layer will give you a mold approximately 6mm thick....enough for all molds up to 100"!

Hope this helps a bit....
best regards


PS: attached you will find 2 plugs for a rudder i just made (they were cnc milled)....after placing the part in the wood and drilling the holes it should look just like that.

RE: RC scratchbuilt Albatross in progress
 

Thanks Hank for the moldmaking info, I will look into those materials and try your process on the next moldmaking project for certain. :) -stef

RE: RC scratchbuilt Albatross in progress
 

Hello again! I'm cruising right along and should finish just in time for my self imposed deadline of August 23rd. (First flights to be Sept 15/16th)

Filling and Sanding:

Nothing too exiting about this step, just hours and hours of sanding then filling, then sanding some more. I know I'm using a what looks like a ton of filler, but what remains after sanding is very thin. It is also very easy to create knifelike edges on the hull which should aid in water release and help this beast get on step sooner.

http://www.stef.com/Albatrosspics/up...07/sanding.jpg


Main Cabin Hatch:

I drew up the front windows then used chartpack tape to dial in the lines. I made a paper right side that I flipped to the left to transfer the lines, then went to work with the dremel.

http://www.stef.com/Albatrosspics/up...tchwindows.jpg


Wing Fillets:

I love the rounded wing fillets on the Albatross and recreating seamless fillets with removable wings was a bit of a challenge. After several passes with more filler, and scoring it before it fully cured, I was able to get the wings to mate with the fuselage cleanly. [link=http://www.stef.com/Albatrosspics/update 8_10_07/wingfillet.mov]Here[/link] is a video of the wing half sliding into place.

http://www.stef.com/Albatrosspics/up...wingfillet.jpg




Fuselage Windows:

I cut out the rest of the openings in the fuselage. Aside from the side windows I also cut out the nose hole which will give me access to my video camera, and the lense window for my digital camera.

http://www.stef.com/Albatrosspics/up...07/windows.jpg

Float attachment:

I started to flush out how the floats attach. I decided against the magnet idea for the floats because I had visions of my floats dropping off the wings after a bounced landing!
I installed tongues that stick out of the wing an inch and a half that with the floats. There will be an inconspicuous screw on the side of each float to hold it on.

http://www.stef.com/Albatrosspics/up...loatattach.jpg

All together:

Well this is a view of most of the big pieces together. I have some more finish work of priming, filling, and sanding to do on the fuse and wings, but I should be able to start the riveting process in a couple of days.

http://www.stef.com/Albatrosspics/up...lltogether.jpg

Until next time :) -stef

RE: RC scratchbuilt Albatross in progress
 

Beautiful work !

RE: RC scratchbuilt Albatross in progress
 

Thanks Charles :)

The Albatross factory is running around the clock now!

First Primer coat:

Although the pics make the fuselage look perfectly smooth, the first primer coat revealed all kinds of little holes and deep scratches that needed to be filled. The second image shows all the imperfections filled with acrylic putty. I will wet sand everything and then move on to rivet and groove work.

http://www.stef.com/Albatrosspics/up...firstprime.jpg
http://www.stef.com/Albatrosspics/up...finalputty.jpg

Detail parts:

I went ahead and made all the little super tiny parts that will make this plane look very realistic. From exhaust stacks to antennas of all sorts, I think I've covered most of the little details. I will make a mooring line that splits and goes around the radome as well. The second pic shows the heat forming of a wing tip light cover with left over yogurt lids. It worked very well.

http://www.stef.com/Albatrosspics/up...3_07/parts.jpg
http://www.stef.com/Albatrosspics/up...07/wingtip.jpg

I will post more updates as parts come flying off the assembly line this week :) -stef

RE: RC scratchbuilt Albatross in progress
 

The floats are finished! Now on to gear mechanism and gear doors. :) -stef

http://www.stef.com/Albatrosspics/up...floatsDONE.jpg

RE: RC scratchbuilt Albatross in progress
 

:) This is amazing work that you have done. I would liek to have a copy of those plans too whenever you get around to making them up. And whou would make the landing gear?

RE: RC scratchbuilt Albatross in progress
 

Thanks Don! Once I got the geometry correct for the gear, it wasn't all that difficult to make the gear out of carbon tubes. It was a bit tedious, but with some fine dremel bits and some patience they came out great.

More progress:

The gear doors and gear are now finished. To weather the parts I just brush on black acyrlic (I think) paint, then sponge off. Then I fix it with acrylic spray. I've attached all the little details to the wings and fuselage, and drawn out all the lines I need to rivet and groove. :) -stef

http://www.stef.com/Albatrosspics/up...18_07/gear.jpg
http://www.stef.com/Albatrosspics/up.../geardoors.jpg
http://www.stef.com/Albatrosspics/up...lsandlines.jpg

RE: RC scratchbuilt Albatross in progress
 

This is just incredible.....dang! I am not sure what else to say, but this is like a VERY Good movie. Keep posting pics. If you would not mind, please dont sleep for the next three weeks and only work on this, so we all can get back to our lives! Nice job

RE: RC scratchbuilt Albatross in progress
 

You may have shared this already and I have missed it but would you mind sharing the technique you use to put on all those rivets! I don't have that many to do in compairison, but the right look is everything! I am amased!!!!!!!!