My Fokker DVII Project

Maxim08 · 10 March 2007, 02:39 PM

Jeff,
Attached is a photo of a Ranger engine mount in the GWFM's D VII.
Note the oversize washer and the equally large circular rubber pad between the engine bearer and the washer/engine mount assembly.
It looks like you have come up with a good solution but, since no one else responded, I thought I would get a photo for you.
Regards,
John

Jeff Brooks · 10 March 2007, 04:57 PM

That is great Maxim08!! Did you get any pictures that shows how far forward the engine is relative to the forward cambane struts? I have been looking at the placement of the BMW & Mercedes and the first cylinder looks to be well in front of the forward cambane strut. The Ranger is a way smaller engine and it would leave quite a bit of rome behind it for battery, oil cooler and other toys! If you could, can you get me a picture that shows the rest of the arrangement and how the magnetos clear all the tubing underneath it!?!

Maxim08 · 10 March 2007, 05:53 PM

Here you are Jeff, all is revealed....

Regards,
John

Jeff Brooks · 10 March 2007, 08:14 PM

John, this Picture is awsome, exactly what I have been looking for!!! you have saved from reinventing the wheel!

Von Writter · 11 March 2007, 11:14 AM

So John, is the nose on the DVII Longer than original due to the lighter weight of the Ranger? Or how did you guys solve the Weight and ballance problems you must have encountered?
Troy W.

Jeff Brooks · 11 March 2007, 12:30 PM

Von Writter, Yes the engine is definitely moved forward significantly! about 5-6 inches as far as I can tell. It might be for weight & balance reasons or just because the frame won't allow a ranger engine in the correct position.
The BMW or Mercedes IIIa have the magnetos on the top & back of the engine,

But not so for the Ranger or Gypsy engine. The magnetos get in the way in the bottom truss work of the engine bears. You have to compromise with how to get the magnetos to fit. They either split the magnetos & engine case, or go completly inside the trusswork.

greatwarpilot · 11 March 2007, 12:43 PM

Quote:

Originally Posted by Von Writter

So John, is the nose on the DVII Longer than original due to the lighter weight of the Ranger? Or how did you guys solve the Weight and ballance problems you must have encountered?
Troy W.

I believe the engine in our DVII is moved forward within the cowl, but the external deminsions are correct to the original. The small size of the ranger relative to the Mercedes (as explained by Jeff) allow for this.

We have added lead to the nose of the airplane to try and compensate for the lack of weight, but the most appropriate answer is probably that we have yet been able to fully solve the w/b issues of the DVII with a ranger engine. That being said, even with the less than ideal results the aircraft has been flying since 1977 and has over 650 hours on it.

Jeff Brooks · 11 March 2007, 12:51 PM

Of course other options include getting your hands on a BMW or Mercedes or moving the trusswork under the engine bearers.

I had to go through all kinds of trouble to get the engine moved again! In order to move the engine by myself without tearing up he paint again, I had to lift the front and remove the landing gear ....

I made my frame exactly like the Replicraft drawings, and the engine bearers are the correct size, but when I move the engine so the entire magneto & engine accessory gearbox is between the trusswork, the front mount hangs over the bearer ...

I will have to splice some more tube in there for it to be safe & give me something to attach the radiator cover to.

With the added length, the plane bearly fits inside the garage.

By the way, after attempting to fit the engine mounts with the new rubber adaptation, I found that one of the four engine mounts was still good. Instead of tearing out the good bushing (knowing how difficult they are to find), I figured I ask around if anyone has one that has a torn bushing and I'll trade.

Jeff Brooks · 11 March 2007, 03:05 PM

To give you a comparison of how far forward the nose was extended, here is a picture. The cardboard cowling is made directly from an original Fokker drawing, and the rear edge lines up where it should be mounted. The round portion should overlap over the sides of the radiator. If you look carefully, you can see on the fiberglass radiator the curved area where they should mate up.

Jeff Brooks · 11 March 2007, 04:05 PM

If you look closely at this picture of Roger Freeman's plane, you will notice the magnetos are between the trusswork, keeping the engine back in the correct position.