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Chevelle 11-06-2004 06:56 PM

Fokker DRI Build Along
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Ok Gang. Here we go.

The kit is Balsa USA's 1/4 scale Fokker DRI Triplane. I built their Sopwith Pup last year and really enjoyed the building experience. (It flies great too!) From my experience with the Pup and from the looks of the Triplane so far, the build will probably be pretty straight forward but I wouldn't recommend either as a first kit. Not because they are hard, but rather that they are big and there is more to them since they are a biplane and a triplane respectively.

My plan is to built the kit per the plans with two exceptions. I intend on building a pseudo-scale bungee suspension undercarriage and a scale-like pull-pull system for the control surfaces. I will power the plane with a Zenoah 26 gasser, just like I did with the Pup. I'm not yet committed but I am considering a smoke system. I have a Fiberglass Specialties cowl to replace the BUSA ABS one and I plan to put in Glenn Torrance's cockpit and dummy engine kit. Finally, I figure I will use doped and painted Super Coverite to finish it off.

- - - -

I opened up the DRI and quickly noticed that the whole box was FILLED with wood. Like I said, there is a LOT to a triplane. Everything was neatly organized and the quality of the wood seems excellent. I would recommend that you create little piles of similar parts. That will make it easier and faster to find parts without having to rummage through the box each time. I made stacks of rib sheets, bundles of stringers and cap stripping, stacks of sheet wood, etc.

The kit is die cut but don't let that turn you off from building this kit. The cutting is of high quality with little to no crushing on the side that the die hit first. The parts almost fall out and require very little sanding if at all.

The Bottom Wing
Per the instructions, I started with the bottom wing. The instructions are very detailed with lots of black and white pictures. If there is one gripe (and it is minor) it is that there is a lot of detail in the pictures and given their size and they aren't high contrast, it is sometimes hard to see the detail that they are referring to in the text. In most cases, that isn't a big deal.

The construction is straight forward. Pin down the spars, leading edge, trailing edge, and then sprinkle liberally with ribs. Unlike the Pup, the Triplane uses a double leading edge and capped ribs. Neither is a big deal but it was different, at least it was for me.

Since the wings are one piece and relatively long (~70in), the spars, trailing edges, and leading edges have to be spliced. The instructions are very clear and easy to follow regarding the splicing technique for those that have never done it. They even remind you (several times) not to have all the splices line up on the same side. (That weakens the wing.)

Here are some pics. The middle wing is next!

jbloom 11-06-2004 07:38 PM

RE: Fokker DRI Build Along
Looks nice Chevelle.. I'll look forward to watching this one come together.

BruceLBarner 11-07-2004 07:57 PM

RE: Fokker DRI Build Along
Looks nice
Got a VK tri-wing I send ya to build next......hehehe

Chevelle 11-07-2004 10:52 PM

RE: Fokker DRI Build Along
Thanks guys. The middle wing is almost done. I'll post the next installment in a few days.

Bruce. No problem. Just include your credit card when you ship it ;)

bps 11-08-2004 07:19 AM

RE: Fokker DRI Build Along
Good idea on this thread. Seems to be lots of interest in this kit and more than a few builders. I have the sub wing, tail feathers, bottom wing built as well. Looks like the G26 is a great choice and I have a new one in the box for this project too. My wing took a horrible warp upon removing it from the building board. Very strange, as I have never had this happen before. Any thoughts on radio, servos and batteries yet?
Keep up the good work.

Chevelle 11-08-2004 08:51 AM

RE: Fokker DRI Build Along
Sorry to hear about the warp. I haven't had that happen with either the bottom or middle wing. We'll see about the top :)

I am going to stay with what worked with the Sopwith Pup. I'll probably go with a 1100-1400 mAh battery. I'm OK with Hitec servos. I put 425BB and 635HB servos in the Pup and they seem to work fine. I had a bad experience with a Hitec's receiver so I will go with a JR.

I'm real happy with the Zenoah that went into the Pup so why mess with something else. I haven't ordered it yet but that is the plan.

If I add smoke, I'll probably go with an electric pump version. According to the BUSA instructions, the model should build out a bit tail heavy. The additional battery placed up front should help out. I won't need a large smoke oil tank since my goal isn't to use it as part of an aerobatic performance. It's just for "dog fighting" effect. Short occassional bursts followed by a sloppy roll or other simulated hit effect. Just for some fun.

Feel free to join in with comments and suggestions any time.

P-40LUVR 11-08-2004 10:17 AM

RE: Fokker DRI Build Along
The build is looking great so far!
Where do you get those clamps you used for the wings?
Are the adjustable?
I will be needing something like that when it comes time to construct the wing for my Tomahawk.

bps 11-08-2004 05:11 PM

RE: Fokker DRI Build Along
A great source of clamps are the thick paper/binder clamps you can get at the office supply place. They are cheap:D and work very well for a number of clamping choirs.

P-40LUVR 11-08-2004 05:25 PM

RE: Fokker DRI Build Along
I use those kind of clamps for clamping thick balsa parts but as you can see on that wing build I think those paper clamps would either not open far enough or go through the thin balsa sheet on the wing.
It would be nice to have some plastic ADJUSTABLE,type of clamp so you can get just the right tension on the part.

Chevelle 11-08-2004 06:45 PM

RE: Fokker DRI Build Along
About half of those clamps I got from the super market! Up here in Rochester we have Wegmans, which is the most unbelievable market that you have every seen. They have this kind of bargin table with kitchen stuff on it. I got some of those clamps that you see in the picture. I also got a bunch of real small clamps as well. Very inexpensive. Like $1.99 for six. Something like that. The rest of the black clamps you see in the picture came from an assortment pack at Home Depot. (They are the exact same clamps.) With it came the two adjustable clamps that you see in the picture a two larger "beam-type" clamps. $9.99 for the assortment.

Bruno Stachel 11-08-2004 09:52 PM

RE: Fokker DRI Build Along
Cool project Chevelle. Have you decided on a pilot or unit you will decorate it as? Looking down the road, I'll be curious to see if you top your Pup video.

Chevelle 11-10-2004 12:35 AM

RE: Fokker DRI Build Along
1 Attachment(s)
Round Two...

The Middle Wing

The middle wing builds just like the bottom one (as will the top.) So that should make it easier and go a bit faster but of course, that's why I made a mistake. As mistakes go, this one was pretty minor. The instructions clearly state that the lower spar should be placed on the lower sheeting. I placed the spar down on the plans and then attached the sheeting, gluing it along the side of the spar. Oops.

I didn't notice what I had done wrong until I went to add the first ribs. The spar didn't fill the cutout for the spar because the spar was sittin too low. The fix wasn't difficult. I took the scrap pieces for the bottom wing cap strips and glued them to the top of the bottom spar. That raised the height so that the spar now fit the rib cutouts. The added weight will be negligible. It also made for a stronger wing! I also made sure that the glue joints between the lower spar and the sheeting will good and complete. No harm, no foul.

The instructions suggest that you use a coffee can to sand the scalloped edges. I chose an almond can. It worked just fine. The wings are just rough sanded at this point. I'll finish sand them before covering.

For the record, it took about four evenings to build each wing, 2-3 hours per evening. I don't build all that fast so your mileage may vary.

The next step is the top wing.

Chevelle 11-10-2004 12:36 AM

RE: Fokker DRI Build Along
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Two more pictures...

CafeenMan 11-10-2004 06:19 AM

RE: Fokker DRI Build Along
It looks like Balsa USA has improved their die-cutting a lot since I last built one of their kits. Either that or you did a lot of sanding. Good looking construction. I noticed the wing tip in your first post is angled up. Is that scale? I've never closely looked at a DR1.

Chevelle 11-10-2004 07:17 AM

RE: Fokker DRI Build Along
I would say that the die cutting on both the Pup and Triplane is excellent. Minimal sanding of the separate parts is required. They come out with very little pressure and the fit is very good. I certainly wouldn't avoid the kit(s) just because they are die cut. Of course, as you have observed, I am an excellent builder so that makes a big difference. :) (Not really. I would say that my skills are averaget to slightly above average. These kits are not hard.)

I believe the Fokker does have wing tips that raise up on all three wings.

WinterHawke 11-11-2004 10:27 PM

RE: Fokker DRI Build Along
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ORIGINAL: Chevelle

I believe the Fokker does have wing tips that raise up on all three wings.
Good evening, Chevelle . . .

Actually, the original Dr.1 Wingtips are slightly curved, following the center of the rib. A couple of good photos of this can be seen over at www.fokkerdr1.com on the Voss machine:


and even better:


I've got my own Balsa USA Triplane to the almost ready to cover stage, and am incorporating numerous changes for scale details, slowly and skillfully tangling myself up along the way :eek: !!! But it's been fun so far - now I get to rebuild the undercarriage, as it didn't pass muster under peer review this last September (bye the bye, mine has scale-like wingtips on the top and middle wing, and originals (to be changed yet) on the lower wing for comparison).

Looking forward to following your build - I'm sure you're going to enjoy!!!

'til later,

dicknadine 11-12-2004 11:18 AM

RE: Fokker DRI Build Along
sure have enjoyed your build along. it makes me wish I wasn't a scratch designer/ builder. have releaized that you don't save much money this way but a lot of time, scatching the head trying to figure out the next move. KEEP it UP. dick

Chevelle 11-12-2004 02:06 PM

RE: Fokker DRI Build Along
Stay tuned for important developments!!!

I have begun the top wing but more importantly, I have started to think about the scale aileron control scheme. I want to use pull-pull cabling but don't want a lot of hassle and more importantly, I want it very reliable.

I am an engineer and use 3D CAD tools regularly. I have modeled up what I believe to be a very easy yet effective way to do scale aileron control within the wing. I'll be posting illustrations and even an animated movie soon. This method should work for lots of planes, not just the Fokker or WWI vintage planes.

Chevelle 11-13-2004 01:06 AM

RE: Fokker DRI Build Along
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Here is what I intend to use for the aileron controls....

I'd rather not bury servos out at the wingtips and deal with rigging the servo with it in place. This is what I came up with. It allows the servo to be placed anywhere where it is convenient. You can even use a single servo with the appropriate strength! Removing servos doesn't require you to re-rig the aileron control.

It uses two bell cranks. In this case the short arm is 3/8in from the pivot point as measured from the pivot point to the hole. The long arm is 3/4in. The cranks are are mounted opposite one another so that the connection points for the rigging are right on top of eachother when the setup is neutral. Standard control rod swivels are used to attach the cranks to the control rod.

When the rod is pulled, the top crank pulls the cable forward while the bottom crank moves in the opposite direction. This moves the aileron up. The directions are reversed when the rod is pushed and so the aileron moved down.

I haven't decided where I am going to mount the servos. I may even consider just one.

Chevelle 11-13-2004 01:41 PM

RE: Fokker DRI Build Along
Great picture Lee. I'd love to know how you did the rear skid and how you intend to do the undercarriage. You are ahead of me so your insight would be very helpful. I didn't realize that the scale wingtips were so different than the kits. I wonder why BUSA did it this way. Their Pup has tips similar to the what you have done.

I'd also like to know how you intend to do the pull-pull setup in your plane. I've never done one before. I want it simple but reliable.

WinterHawke 11-16-2004 12:34 PM

RE: Fokker DRI Build Along

ORIGINAL: Chevelle

Great picture Lee. I'd love to know how you did the rear skid and how you intend to do the undercarriage. You are ahead of me so your insight would be very helpful. I didn't realize that the scale wingtips were so different than the kits. I wonder why BUSA did it this way. Their Pup has tips similar to the what you have done.

I'd also like to know how you intend to do the pull-pull setup in your plane. I've never done one before. I want it simple but reliable.
My dear Chevelle,

Sorry I couldn't get back to you sooner - was away over the weekend sans computer!!

Thanks for the compliment, but still got a ways to go. Answers to your questions as follows:

The rear skid is faked out right now - it's only balsa simulating the final shape - trying to get the look right. My triplane version is going to be modern replica N220TP out at Rhinebeck, and numerous items on that plane aren't as Tony Fokker did 'em back when. I haven't decided how to affix the skid yet, as I'm torn between making it shock absorbing, and just mounting it as simply as possible (ala Great Planes). I need to get some weight out of the tail, so I'm kinda leaning towards simple, also figure that the tailskid shouldn't take too much of a beating. One of the many mind traps I've wandered into with this bird!!!:D

The undercarriage will be a version of the Flair Triplane mod eloquently described by Alan Morgan over at:


except I'll use large (probably 8/32) bolts in place of nails for the shock cord mounts, and these same bolts will hold the landing gear plates to the subwing using hardwood blocks alongside the axle box. I'll try to sketch something in a few days to show.

The wingtips as done by BUSA are fine, unless absolute scale is what you're after. Simple, good looking, functional - everything but scale! Mine are laminated, and glued together on a form to get the airfoil shape - definitely fiddly. But I think they will work out fine nonetheless.

I really don't expect the pull/pull to be an issue. I've purchased two servos to bury in the wings, and will mount them lying down onto a plate which will mount from below (round, simulating a convenient access plate on the replica). Ball joint clevises on the servo wheel, and there you go! The tailfeathers will use the same hardware. Back in the olden days when I flew pattern, I used ball joints for rudder cables with great success - I expect nothing less here. Again, I'll try to sketch something up over the next few days.

Other mods I've got going are replacing the BUSA cowling with one from Flair (matches the replica shape better), scalish strap hinges, control horns from Proctor, scalish wing interplane struts, etc. . . . which explains why mine's been under construction since last year's Dawn Patrol in Dayton!!! (That and the known fact that I am a notoriously slooooowwww builder :eek: ).

'til later,

AlphaWhisky 11-17-2004 05:12 AM

RE: Fokker DRI Build Along
One of these has been on my short list for a while now. I have a set of plans and instruction manual only for this model - no kit materials at all.

Based on your experience using the kit components to date, do you reckon building from the plans only will be a straightforward exercise?

Alan W

Chevelle 11-17-2004 07:19 AM

RE: Fokker DRI Build Along

I think the build would be straight forward but your materials list will be quite long. That box was filled to the brim with wood. I doubt that you could purchase all the materials for less than what the kit cost not to mention the benefit of not having to cut all those ribs.


Thanks for that link. I will be using that as a reference when I get to that point.

I was at Rhinebeck in September and knowing that I was going to do the DRI, I took quite a few digital pictures of the Fokker. I can get them to you if you need them as additional reference material.

When I did the Pup, I wanted a more realistic skid than just the bit of wire that they provide although I did not go for a bungee suspended tail skid. I took a piece of music wire and bent it in the shape of the skid. Then I placed it down on a piece of scrap basswood and traced it. I flipped it over and traced it again. I used the dremel ball mill and cut a groove between the traced lines and then rough cut out both halves. I filled the groove with epoxy, put in the music wire with about a half inch sticking out on one end and then put the halves together in a vice overnight. It was then an easy matter of sanding, staining and varnishing the finished skid. The final touch was a brass skid plate and the cut off heads of tiny brass screws in the plate. The extended music wire allowed me to mount the skid so it would swivel. That was unnecessary. A fixed skid would have been fine. I'll make a skid for the Fokker the same way bit I think I will make it a bungee suspension.

Where did you get the 1/4 scale pilot in the picture? I'll want an authentic looking pilot for my plane as well. I also see that you made a custom rudder, complete with airfoil shape. Was that for a more scale like appearance or for flight characteristics?

I finished the upper wing and have started the fuselage. An build update will follow.

WinterHawke 11-17-2004 01:23 PM

RE: Fokker DRI Build Along
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I like your thoughts on the tailskid - was considering the idea of a buried p.w. gear as well, glad to hear that it works!!!

The pilot is from Proctor Enterprises - in their catalog as "AH Design World War 1 Pilots" - my good friend Doug Cox in Zinzinnati had him shipped to me for Christmas last year - he does look good, and is surprisingly light. Also Del Johnson (aka von Delby / Deljon) has the same pilot for his Torrence Fokker D.VIII, and has removed the leather helmet - actually looks even better! Check out:


I decided to go all out on the rudder. I blew up the 3-view from the datafile until the area matched the BUSA unit, and built it up using a laminated ply core and balsa ribs and outline. A bit heavy, but very strong (I've got this nervous feeling that the top of the rudder may get some grass stains on it from time to time :eek: ). Definitely for show, from what I've seen, the stock BUSA Tripe flies just fine.

I definitely would like to take you up on your very kind offer on photos - I'm weak on the area of the tailskid and cockpit on the ORA Tripe. I've managed to find and/or acquire a good selection of photos on the web, but like you are well aware, we can never have too many photos!!! :D :D :D

'til later,

Chevelle 11-17-2004 02:54 PM

RE: Fokker DRI Build Along
Send me your email address and I will email you a zipped file with the pictures.


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