Whirl Wind 200RV and Cowl Conflict

I am installing a Whirl Wind 200RV prop with a standard Van?s cowl. My propeller came with a two piece back plate. The two halves of the back plate are held together by the mount plate and three bolts on radials from the center of each side of the cowl back plate. Two of the three bolts are on about a 45 degree angle to the face of the plate and one is on the outer diameter of the back plate. The two bolts on the angle are rubbing my cowl. Has anyone else had this problem?

I set my cowl spacing a long time ago using a single piece back plate from Whirl Wind and I?d rather not make adjustments to the cowl at this point. Whirl Wind feels like the screws are necessary to keep the back plate from vibration and eventually cracking. They suggested trimming the cowl. I am thinking of replacing the round head screws with countersunk screws and tinnerman washer.

Comments?

Tumper said:

I am installing a Whirl Wind 200RV prop with a standard Van?s cowl. My propeller came with a two piece back plate. The two halves of the back plate are held together by the mount plate and three bolts on radials from the center of each side of the cowl back plate. Two of the three bolts are on about a 45 degree angle to the face of the plate and one is on the outer diameter of the back plate. The two bolts on the angle are rubbing my cowl. Has anyone else had this problem?

I set my cowl spacing a long time ago using a single piece back plate from Whirl Wind and I?d rather not make adjustments to the cowl at this point. Whirl Wind feels like the screws are necessary to keep the back plate from vibration and eventually cracking. They suggested trimming the cowl. I am thinking of replacing the round head screws with countersunk screws and tinnerman washer.

Comments?

Click to expand...

... Mine did exactly the same thing! I solved it as you suggested, you will love this prop. Thanks, Allan...

reinforced and trimmed it

I reinforced the fwd face of the cowl with heavy boat cloth and trimmed the fwd face. I think I have about an inch of fwd face all around.

Tumper said:

I am thinking of replacing the round head screws with countersunk screws and tinnerman washer.

Click to expand...

That's precisely what I did. 200 hours and no issues!

Try again

OK. I did what Mike and Allen suggested and I still have some interference so I guess I am going to Phase II. Now if I could move the cowl back just a little there wouldn’t be a problem but everything is set on the rear of the canopy. No moving now.

As Steve suggested I guess I will trim off the angled surface (where the interference is, see picture) to the forward face and reinforce the forward face.

Note: This is an old photo before the cowl was fitted. I am using it to point out the area of interest only.

Has anyone else had to do this? Comments?



Sorry, I just looked at this picture again and the cowl looks pretty bad. It was a used cowl and I have since "cleaned" it up and it looks a lot better now.

Bolt direction/clearance issues and Whirl Wind suggestions

I'm reviving this thread because I'm installing my Whirl Wind 200RV prop now. Following the directions for installation, I bolted the temporary spinner installation plates to the spinner mounting plates, with the bolts installed from the back side as specified in the instructions.

Then I bolted the prop to the engine per the assembly sequence, tightening the bolts but not torquing to spec yet. The instructions called for removing the installation plates and bolting the two-piece bulkheads to the spinner mounting plates... but I found that with the bolts inserted from the rear as specified, I coudn't remove them because they contacted the ring gear before clearing the spinner mounting plate.

This obviously wasn't right, so I called Whirl Wind and talked to Jeremy, describing the situation. He understood my predicament and was surprised they hadn't gotten any other calls about such a scenario. He wanted to double check some things and call me back, so I came here, found this thread and saw that other builders installed the bolts through the front side. When Jeremy called back, he concurred that that was the correct solution. I will loosen the prop enough to remove the bolts, reinstall the bolts from the front, through the spinner installation plates and spinner mounting plates, re-tighten the prop, remove the bolts and install the bulkheads. He also gave me three tips that other builders can benefit from:
1. Leave spinner off for first engine run. Torque prop bolt (actually a stud/bolt/roll pin assembly) to spec, but do not safety wire yet. If the engine/prop is vibrating from imbalance, you may want to re-clock the prop 180 degrees to see if that helps prior to dynamic balancing.
2. Clearance issues while applying safety wire to the prop bolt may require that you loosen the bolt slightly to run the safety wire, then re-torque to spec. Don't safety wire until after the first engine run and you know it's on for good.
3. PROTECT YOUR PROP VERY WELL! The trailing edges of the composite prop are very susceptible to nicks from dropped tools during assembly. Wrap the props very carefully with padding to prevent any damage until just before running the engine.

Fair warning: Safety wiring this prop is no fun at all.

erich