LOL! I can't tell you how many people suggested that I make my Dr1 a hanger queen, Bill. A friend of mine is begging me to do so, but I can't. It's such a hit at the club and at shows if it's a very very good day then I'll fly it. In the State of NY where I live, having no winds is very rare. So in other words I only fly her only on special occasions.
My Hanger 9 Fokker DVII I had for 4 years and she looks the same when I just finished building her. I too had a problem with the cowl fitting, but with a little heat from a hair dryer and by not giving up I finally won the battle.
When I first completed the DVII I had installed a Evolution .61NX in it, but after 2 years of having cooling issues- then loosing a prop in flight, I killed my engine. I'll not ever buy a Evolution 2 stroke glow ever again. I did hear that the new Evolution Radial Engines are fantastic. They are made from a different company under the same Evolution banner.
So after that happened to me I switched the engine over to a O.S. 61FX and I haven't had any problems of any kind. It flies scale but the only problem I now face is when I pick a mock dogfight against a 1/4 or 1/5 scale Allied WWI plane, most of them have a more powerful engine installed. Here I am flying scale, and they out run and out climb me every time. [:@] Dem B@st@rds!
But that's OK, Hanger 9 based their model on a early D7, not the later DVIIF. If I were to re-model the plane then I'd have a 91FX or equivalent in it after first modifying the cowl. Now if I were to take the Dr1 out into a fight, look out! That O.S. 91FX is powerful and I could go toe to toe with any 120FS that's out on the market. In my maiden video you can see how she leapt in the air even at 5lbs over weight!
Don't forget if you choose to buy another Hanger 9 DVII legs, your going to have to do a little bending so the GP landing gear wing will sit tight on the inside. If you don't then you might have to add spacers and use longer screws to go in the landing gear wing. I also had to hollow out the GP landing gear wing with a very long industrial drill bit, so the steel axle rod would fit through (without any resistance) when I moved the axle up and down once the wing was screwed in place. You might have to strip the Mono covering of the landing gear leg, assemble everything then re-cover to make sure you line up everything to make it work. That way if you make a mistake, you can fix it, make sure your screw holes line up etc.
That's what I did, if you know of a easier route go for it. Let me know how you made out no matter what you decide to do and send me a picture if you have the time. If you run into a problem don't be afraid to chime in, I'll be here for you. One thing I learned is that Fokker Dr1 comradery is second to none no matter if it's a kit, scratch built or ARF. Not everyone can handle a semi-scale Fokker DR1 IMHO. The only plane I can think of that would be harder to fly is the GeeBee R1. I would have to say a few "Hail Marys" before I flew one of those.
The OS .90fs is a fantastic engine and will work fine for your D7. Is it a before surpass if I remember right? Geez they date back to the 70's through the 80's! It's equivalent to a 60ts. I think the Saito 82 would be a good choice as well. Not sure it would have the same power as your older but goodie O.S. engine, but it will work. I love O.S. and Saito, and I really like the older classic engines. I also enjoy rebuilding them when the time comes. It's like another hobby all by itself!
Pete