[apatti]

OK, I researched this and found nothing. How do you fit/install the lower cowling on an A model with a 3 blade prop? I have cut the slot in the lower cowling for the nose gear 14 inches long. Do I need to make the slot longer?

Thanks,

 

[steveciha]

OK, I researched this and found nothing. How do you fit/install the lower cowling on an A model with a 3 blade prop? I have cut the slot in the lower cowling for the nose gear 14 inches long. Do I need to make the slot longer?

Thanks,

As i remember it, the construction manual tells you to cut the slot about 3 or 4 inches longer than you would for a 2 blade prop. Anyway, that is what i did for my Whirlwind 3 blade prop. Then i made a good fiberglass fairing to cover the extra long slot that screw attaches to the rest of the cowl. Even then it was difficult to get the cowl off and on. The blades needed to be exactly in the right place for the cowl to come off.

steve ciha

 

[glider4]

Cowl slot for 3 balded prop

It's in the construction drawings. My slot ended up being about 12.5 inches long. See in the picture the horizontal marks in the middle of the slot that mark where the nose gear leg passes through the slot. You need to rotate the cowl as it comes off to clear the blade. Looking from front to tail, I rotate the cowl to the right and down to clear the right blade. You also need to fabricate a front "spacer" like the rear spacer to fill in the section of the slot forward of the gear leg. Again, it's in the construction drawings. I'll get the drawing number for you tomorrow if it's not posted before then.

Albert Thomas
N880AT
RV-8A QB
wiring.......

 

[apatti]

Thanks for the replies. I saw in the manual where it says you need to cut the slot longer for a 3 blade. I was just getting nervous that I was cutting it too long. I have the drawing and didn't see where any length was specified (just a width for the slot). However, the drawing is very busy so I could have missed it.

I was finally able to work it in place by twisting it to the side and then rotating the prop and sliding it up. I figure once I do it a few times I will learn the "combination."

Thanks again...

 

[Rupester]

Send a PM to VAFer DB1YG ... Dave has some good advice on the A model cowl vs 3 blade prop situation. I talked to him about it in July when I was in San Antone.

Terry

 

[LifeofReiley]

RVator

One of Van's RVator newsletters has an article on cowl mods for easy on/off if your installing a three blade prop.

 

[macrafic]

One of Van's RVator newsletters has an article on cowl mods for easy on/off if your installing a three blade prop.

Reiley, any clue as to the year, maybe even the month, that this article appeared?

 

[painless]

Regarding covering up the nosegear slot in the cowl for a three blade. Bob at Fairings-Etc makes a really nice nosegear fairing that extends both forward and rearward to cover the slot completely. I have one on my 6A with a Catto three blade and it works and looks great. Check it out here...
.....http://www.fairings-etc.com/



Regards,

 

[LifeofReiley]

Reiley, any clue as to the year, maybe even the month, that this article appeared?

I should have the copy on my desk at the hangar... will look today and report back.

 

[rvbuilder2002]

One of Van's RVator newsletters has an article on cowl mods for easy on/off if your installing a three blade prop.

These mods are helpful with two or three blade props.

Regarding covering up the nosegear slot in the cowl for a three blade. Bob at Fairings-Etc makes a really nice nosegear fairing that extends both forward and rearward to cover the slot completely. I have one on my 6A with a Catto three blade and it works and looks great. Check it out here...
.....http://www.fairings-etc.com/

Regards,

I doubt if Bobs fairing will cover the opening required for many of the three blade prop installations.
I was the first person to install a three blade on an RV-6A (1992). You need a slot length that allows for easy removal and installation. Don't make it difficult or you will be making a mess of your paint after a while.
The reason no specific length can be stated is that it depends on which model RV you are talking about, and which engine size (different cowlings).

For example, an O-360 cowl for an RV-8 has a deeper induction scoop than the cowl for an O-320. The 360 cowl will require a longer slot because the bottom of the scoop is lower and will drop lower on the gear leg during installation and removal.
You need to just make the slot long enough to work well for you installation. Then make a cover using .032 or .040 aluminum with screws spaced about every 1 1/2 inches. this will add the lost stiffness back. Removing the cover every time you remove the cowl is just dues you have to pay for using a three blade prop.

 

[USCANAM]

We have an IO-360 with a MT 3 blade prop, and this was a major headache working the lower cowl.
Here's a list of things we did to help solve the problem.
1. Make covers to go over your 2 lower prop blades when installing or removing the lower cowl. We used padded imitation leather with velcro.
2. We cut the slot as per the plans, and was still too tight. Wrap your nose gear leg with masking tape or something to protect the powder coating.
3. Use the fairing from Bob at Fairings etc, and once installed, you can see how far back you can cut the slot. Unfortunately, you can't properly determine this until you've installed the nose gear fairings. However, you can come close, just leave a little fudge factor. If I remember correctly, you can go at least another 1 1/2" more than the plan shows if you are going to use Bob's fairings. Every little bit helps.
4. Installing the cowl and getting all the rubber baffles in place is really difficult. We mounted the lower ones on the outside of each air intake. Will try to find some photos for you.
5. I sit on a low stool right in front of the plane and use arms and legs to support the cowl. It seems to come off easier than it goes on. You'll see what I mean.
Nicking the blades on my composite prop blades was my biggest worry, especially since I'm using the piano hinges along the top outer edges of the lower cowl.
Hope this helps
Jack

 

[rvbuilder2002]

We have an IO-360 with a MT 3 blade prop, and this was a major headache working the lower cowl.
3. Use the fairing from Bob at Fairings etc, and once installed, you can see how far back you can cut the slot. Unfortunately, you can't properly determine this until you've installed the nose gear fairings. However, you can come close, just leave a little fudge factor. If I remember correctly, you can go at least another 1 1/2" more than the plan shows if you are going to use Bob's fairings. Every little bit helps.

Just to clarify...If this is an IO360 with horizontal induction using the snorkel, it does not require as long of a slot as an O-360 with an MA4-5 carb. The vertical induction O-360 cowl has a very deep induction scoop. Because of this, it comes down lower on the gear leg than any of the other cowl models will.

 

[USCANAM]

Just to clarify...If this is an IO360 with horizontal induction using the snorkel, it does not require as long of a slot as an O-360 with an MA4-5 carb. The vertical induction O-360 cowl has a very deep induction scoop. Because of this, it comes down lower on the gear leg than any of the other cowl models will.

We have the vertical induction.
The induction system doesn't seem to figure in the problem. It's just the cowling moving forward and making contact with the blades as it is lowered.
You can try to remember all the angles and turns you have to make to remove the cowl, which in my case removes quite easily. However, if you try to duplicate the same moves in reverse when installing the cowl, it seems to jam....must be the high humidity!!!!!
I have less than a 1/4" between the back edge of the spinner and the cowl...that doesn't help either.
Having a helper is good too, but not necessary.
After about a dozen cycles or so, you start to get the hang of it.
BTW, I did an oil and filter change yesterday without removing the lower cowl. Made cleaning up after a little more difficult, but was able to do my routine check of connections looking into the back of the lower cowl using a light and a mirror.
Jack

 

[rvbuilder2002]

With have the vertical induction.
The induction system doesn't seem to figure in the problem.

You're right. It's not the induction system that matters, I said it was the different cowls for the different induction systems. I have worked with RV's that have all of the different cowls and have found that it does make a difference...but everyone is entitled to there own opinion

 

[USCANAM]

You're right. It's not the induction system that matters, I said it was the different cowls for the different induction systems. I have worked with RV's that have all of the different cowls and have found that it does make a difference...but everyone is entitled to there own opinion

Sorry Scott
I see what you mean with the snorkel. I guess that doesn't make it any easier.
When I ordered my engine, I requested horizontal induction, so we ordered the proper cowl from Van's. When the engine arrived, it had the vertical induction, and it was cheaper and easier just to swap cowls than convert the engine.
Probably worked out better now !!
Jack

 

[painless]

I doubt if Bobs fairing will cover the opening required for many of the three blade prop installations.
I was the first person to install a three blade on an RV-6A (1992). You need a slot length that allows for easy removal and installation. Don't make it difficult or you will be making a mess of your paint after a while.

Sorry Scott, but I must respectfully disagree. My installation, O320, 6A, Catto three blade, has not been a problem. I do place a couple layers of masking tape on the forward surface of the nosegear leg during cowl removal, and I know the proper removal angles to get that lower cowl off with no problems and the Fairings-Etc nosegear fairing I referred to covers the required slot in the cowl with room to even extend the slot further forward if I so desire.

 

[rvbuilder2002]

Sorry Scott, but I must respectfully disagree. My installation, O320, 6A, Catto three blade, has not been a problem. I do place a couple layers of masking tape on the forward surface of the nosegear leg during cowl removal, and I know the proper removal angles to get that lower cowl off with no problems and the Fairings-Etc nosegear fairing I referred to covers the required slot in the cowl with room to even extend the slot further forward if I so desire.

I should not have been so specific to say it would not work for any. I meant it may not work for all cowls. With your O-320 you have a shallower scoop than what is on an O-360 which makes a big difference. It also makes a difference what prop you have (the person who started the thread didn't specify). For example, the O-320 MT 3 blade has blades that are quite wide in cord near the hub. This requires getting the cowl even lower than some other props.