Repairs & Mods: custom cowl, new gear,etc

87 posts in this topic

Posted

Nice looking cone. Keep your eye's peeled for a used Shop Smith. I see at least 3 a year being offered for less than $300 bucks and most have all the  add on tools. The last one I seen on Craigslist was being offered for $150 dollars. I'm tempted to get rid of my old drill press and put an older Shop Smith in it's place just to have the  variable speed on my drill press.

Share this post


Link to post
Share on other sites

Posted

Here's a interesting link for those thinking about spinning a spinner out of metal.  https://www.youtube.com/watch?v=JgRLWAPgD7s

I mentioned people buy wood lathes such as yours and add riser blocks under the head and tail stock to get the clearance needed for spinning. I've seen them take the wheels out of an old pair of roller blades and use them to make spinning tools. After watching the video it will be a little more clear how the roller blade wheels are used. You don't want 6061 as a material for spinning. There are other grades that work better for spinning.

Share this post


Link to post
Share on other sites

Posted

Here's a interesting link for those thinking about spinning a spinner out of metal.  https://www.youtube.com/watch?v=JgRLWAPgD7s

I mentioned people buy wood lathes such as yours and add riser blocks under the head and tail stock to get the clearance needed for spinning. I've seen them take the wheels out of an old pair of roller blades and use them to make spinning tools. After watching the video it will be a little more clear how the roller blade wheels are used. You don't want 6061 as a material for spinning. There are other grades that work better for spinning.

ok i didn't realize what you meant by spinning before just thought you were talking about being able to make a larger diameter plug. I have seen a video of someone doing stuff like that and wrote it off as something i wasn't going to try but now i'll give it some thought. 

Share this post


Link to post
Share on other sites

Posted

9CAF6439-CE01-4E7E-A3EA-640C013E835D.thu10 dollar spinner... I got a 12 cm half sphere iceream mould of the web  https://www.cerfdellier.com/5235-calotte-demi-sphere-inox-de-buyer.html?gclid=EAIaIQobChMIlpXnlen23gIVDvlRCh1H7QvZEAQYDCABEgLOL_D_BwE#/498-taille-o_12_cm Perfect snug fit on the hub plate, drilled a center hole and spray painted it. 

Much faster than starting from scratch. Have you played with Solidworks? It's got some great features to calculate how efficient that spinner/propeller combination is. Here's a link to a YouTube video that can explain what I'm trying to convey: https://www.youtube.com/watch?v=a4lAhFsls5k&t=163s

 

Share this post


Link to post
Share on other sites

Posted

Well for better or for worse i cut the cowling in half and removed the top part from the mold.  Couple reasons, first off i only recently found out how dangerous it is to leave the air filter uncovered so that moisture can get in the engine. I reached in the intake and wrapped some plastic around the filter but not very well. Now i can secure it better. Hopefully the last couple months hasn't destroyed my engine. Fortunately utah is pretty dry usually but we've had 2 or 3 periods of damp weather during those 3 months it was uncovered. Second reason is that i hope to take it to get the new gear brackets welded on soon and a 60 mph wind might have ripped the whole cowling mold off.

I never added the last 2 plies that i previously mentioned that i was planning on. I'm going to see if adding some stiffeners will be adequate. Maybe a little more work and might be a little on the flimsy side but less weight. It feels really light which I'm happy about. 20181201_001854.thumb.jpg.9bd0eddc55d982

1 person likes this

Share this post


Link to post
Share on other sites

Posted

"Damn... I made that!"

Grabbing a beer and saying that  to ourselves is part of the reason we are all so nuts about this money sucking - grown up kids hobby!  

Nice job!

1 person likes this

Share this post


Link to post
Share on other sites

Posted (edited)

"Damn... I made that!"

Grabbing a beer and saying that  to ourselves is part of the reason we are all so nuts about this money sucking - grown up kids hobby!  

Nice job!

Thanks, but it's a long way from done. But I'm more and more convinced that it's not going to end up in the dumpster.

tonight's progress was getting the rest of the cowl off the plane and into my basement shop, so I'm finally not freezing my hands off working on it:20181201_205020.thumb.jpg.ae375369d72ae4

doing the preliminary trimming:20181201_235429.thumb.jpg.a5639ad2137fa6

There are an awful lot of bubbles in this thing. Glad it's not structural or it would be in the dumpster. 

And started getting ready to install the joiner strip between the 2 halves20181201_235440.thumb.jpg.4c2279a0b8620e

I'm using duct tape again as a mold release. 

 

I managed to get the lower half of the mold to come with the cowling when i pulled it off the plane. Some of it will get cut away but it helps the part hold its shape and not deform under its own weight.  I'll need to post cure it at some point.20181201_204954.thumb.jpg.5773dfba52aea5

And you'll notice that i managed to save the circular area around the hub which will help when i join it back together to lay up the joiner strip between the 2 halves. 

 

And we all know the job isn't official until you've shed some blood on it:20181201_205900.thumb.jpg.751194967db75eyes that's really my blood. 

 

Edited by Willja67
2 people like this

Share this post


Link to post
Share on other sites

Posted

Ok guys I'm looking for opinions here on 3 subjects:

1. Right now the cowling is in 2 pieces, top and bottom. I'm considering cutting the top piece in 2. So one piece goes from windscreen to firewall and the other just covers firewall forward.  Right now I'm leaning towards not just for simplicities sake. 

2. Is somewhat related, how many access doors do i need? I figure i'll need to check rotary valve oil and coolant level, but do i even need that? With the wingnut style camlock fastener i can have the top of the cowl off in 2 minutes or less, so again for simplicity I'm leaning towards not. 

3. Should i install some windows in the lower cowl between the door and firewall?

In one of Trent Palmer's videos he had a prop strike and in the aftermath added windows in this location  (about the 6 minute mark). Do you guys think that's worth it? Does it give any appreciable added visibility? I'm a bigger guy and my legs are fairly thick and i wonder if I'd even be able to see out the window if it were there. 99% of my flying will be solo so having the window in the other side might be worth it. His other mod of a forward looking backup camera does seem like it's a really great idea. 

 

Anyways you guys that have experience operating these planes I'd like to be your thoughts. 

Share this post


Link to post
Share on other sites

Posted

I kind of like having the boot cowl as one piece, and the top and bottom ahead of the firewall in two pieces.  Then it's pretty easy to pop off the top of the cowl and have a look at everything.  Maybe  a piano hinge and long joining pin holding top and bottom of cowl together would speed up the removal as well.  If all is good, coolant level and rotary valve oil levels shouldn't change, but of course you wont know that till you've run things for a while.  JImChuk

Share this post


Link to post
Share on other sites

Posted (edited)

I kind of like the two piece no boot cowl solution. Here are my reasons:

1) lighter

2) less complex 

3) boot cowls make working behind instrument panel and thru the firewall a giant pain in the ass.

4) boot cowls make windscreen harder to replace unless boot cowl is removable too, but then what is the benefit of the boot cowl?

Boot cowls do look cool and may provide a bit better fire protection, but that is debatable since it is all fiberglass anyway.

The builder of my Fat Avid did it up as a boot cowl. I converted back to two piece and am super happy I did.

 

Edited by Chris Bolkan

Share this post


Link to post
Share on other sites

Posted

I really need to learn the lesson to not overthink things too much and just go ahead and do something. I spent a week and a half wondering what the best way to temporarily join the 2 halves back together so i could lay up the joiner strip and originally was going to use popsicle sticks with dabs of bondo but that stuff takes too long to set and i finally realized that hot glue and foam had worked well since i started the project and it worked just fine again.

I'm going with the 2 piece cowl. Right now the slight inconvenience of very slightly limited access is far outweighed by ease of construction and however many ounces of weight i'll save. 

20181211_203912.jpg

1 person likes this

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now