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Lower Cowl Slot

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paul330

Well Known Member
Those of you with the MT 3-blade prop.......

It's become clear in these forums that the slot in the lower cowl needs to be extended to help clear the 3-blade prop for removal. Can you give me an idea how much? And presumably you fabricate a panel to fit in the extra gap during normal use?
 
Yep

A friend of mine made the whole scoop removable with camloks for that reason...the three-bladed prop.....and yes, you can cover the slot with a piece of .025.

Best,
 
Here is what I did....

Phil, I finally found these photos.

This is really easy to take on and off and it is flush on the bottom. Make sure you leave a gap for the flex on the nose gear. 210 hours and works great so far. Sorry for the crappy photos but you get the picture.



2rc688o.jpg


1jlus0.jpg
 
Thanks Sean. I will be on to fitting the cowl in the next 2-3 weeks. Is it easier to fit the bottom first, or the top?
 
Thanks, photos were fine! That is just what I had in mind although it looks like a standard length slot for 2-blade?

Can anyone tell me what the extra length of cut-out that is needed to accommodate the 3-blade prop?
 
Phil, Can't remember....I just followed the directions. I believe the top.

I can drop this cowl straight down so I think this would work fine with a three blade.
 
Me too.

I borrowed/stole Sean's design after seeing his plane last year. It's a great idea and easy to build. As I recall, I extended the slot about 5-5.25" but I'd have to measure it; it doesn't really matter, make it as long as you want. I'd post pictures but they look just like Sean's. It sure makes getting the lower cowl off by yourself MUCH easier (assuming you remember to remove it first :)). Another thing I did was put some of that clear 3M tape on the top of my nose wheel leg fairing to protect it from the cowl falling/sliding on it, as well as blown stuff from the prop.
 
I have a removable scoop for the Bowers ram air, and the slot runs up into the scoop opening-----I have only a small amount of the original glass at the front of the cowl to hold the unit together when the scoop is off.

I made a "U" shaped reinforcement out of alum, about 3" wide, .090" thick that helps keep the lower/rear portion from being too floppy, (it is like the front fork brace on a dirt bike) when the scoop is off.

I also made up a filler like Sean did, and added a bit of wet suit material to close out as much of the slot as I could, but allow freedom of movement to the nose leg.

It is still a pain to get the lower cowl off, as it still needs to be carefully jockeyed over the nose pant, and between the two prop blades.

Here is a comparison to a stock 10 cowl.

P3300019.jpg
 
Somebody actually posted the measurement of the extended slot way back when I was doing mine four years ago. I will try and measure mine from the air inlet back and let you know what it is. I would not want any less than I have on mine, because, as Mike says, it really takes two people and some careful jockeying to get the lower cowl off without dinging the wheel pant/gear fairing or the two prop blades. I saved the foam blade covers that came with my prop and always put them on the blades when taking cowls on or off.
 
Thanks for the info guys. I have 2 weeks off to do some serious building so hope to get her on the gear and the engine bolted on :D Next job will be the cowl :(

I suppose there is no reason not to extend the slot almost up to the front intake. My wife is a whizz with the sewing machine so I'll probably get her to make some prop socks and a cover for the front strut - it's always good to make her feel wanted!!
 
Paul, I measured mine today and the forward end of the slot is just 4" aft of the air intake. I fashioned a cover plate that goes in with camlocs. Sorry, I don't have any pics. The setup is working fine at 500+ hours and I have no cooling issues.
 
Thanks Dave, that's the measurement I needed.

I'll be using #6 screws and nutplates but otherwise the same idea......

Off to work!
 
It's taken a while, but I now pretty much have the cowl and baffles done.

I need to make a cover plate for the extended slot on the bottom cowl for the 3-blade prop. How much space forward of the front gear leg do I need to leave to allow for flexing on landing etc?
 
Just bringing this back to the top. I assume that all who have extended the bottom cowl slot for a 3-blade prop have built a cover to fill it in normal use. Can someone give me an idea of how much gap is needed behind the slot for flex of the nose-gear. A useful measurement would be the distance from the lip of the air intake to the back edge of the cover.
 
It is tough to draw attention away from the soap operas here, but a few of us have actual technical questions. How much does that nose gear flex? Like Paul, I extended my slot and now would like to fit a fairing to cover as much as possible. Some of you guys that are flying must have some idea?
 
It's near impossible to tell you how much the nose gear flexes. Some guys drop the nose while I like to lower it as gently as possible. I don't know of any way to measure how much it moves either, from the cockpit.

It has been suggested to me, to use rubber (inner tube or similar) up against the nose strut, so it can flex. My slot extends three inches forward of the cowl/strut intersection and has no cover...and my airplane is one of the fastest -10's around...cruises 202 MPH routinely, if speed is a concern:)

Best,
 
I'll measure

I'll measure the gap between my nose gear fairing and the slot cover I made/copied from Sean. I don't think it's very much, and I know the gear leg fairing hasn't hit the cover or I would have noticed the marks on the nose gear fairing. I'll get to it later today.
cowlgap.jpg

The opening is about 4" from where the gear leg comes through to the gap cover. The gap cover is about 4.5" long. IIRC, the opening is about the same as was specified in the plans, I just extended it with the cover for ease in removing the cowl. It makes a big difference.
 
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