Help with spinner specs for MT on 4-place

[Zzz]

I need some assistance providing some specs for my MT spinner. I've been asked to provide the 1) spinner diameter and 2) the distance from the forward flywheel face to the back of the spinner backing plate.

I have an IO-540-C4B5, but it's not yet hung on the airplane, so I can't do the nose bowl mounting thing. Is anyone with a 540 and a Quickbuild 4-place able to grab that dimension? What is the recommended nose gap?

I have my nose bowl here so I guess the spinner diameter is whatever matches the contours of the bowl? Seems like it would be designed for a standard spinner size knowing Bob.

Thanks.

[PaulSA]

The spinner diameter is whatever the nosebowl size you ordered. I believe that 13" is standard but I (and others) have ordered 14" which looks better. The distance from the flywheel shouldn't be relevant as you fit the nosebowl to the spinner and engine. About 1/4" is a good gap. The other parameter they will need is the lead angle at the front of the nosebowl for a smooth transition to the spinner.

[Bdflies]

ZZZ,, if you go with a 14" nosebowl and are using a 2 blade MT prop, I'll have a deal for you! The MT prop that I'm using came with a 14" chrome carbon fiber spinner. i had to buy a 13" to fit my nosebowl. The plain white unit cost $1,500.00! Chrome was $500 extra...
I have a 14" chrome spinner, complete with all hardware, sitting on a shelf. If you think you might be able to use it, PM me and I'll get some specs for ya. I think there's a good bit, behind the bulkhead that could be trimmed for clearance, if necessary.

Bill

[Mark Goldberg]

Zane, you probably have the white finished nose bowl with the gel coat. That is the nose bowl that works fine with the MT or Hartzell spinner of 14"-14.5 diameter. There is a different nose bowl for the 13" spinner as sold by Vans. As far as gap between spinner aft edge and nose bowl - I like 1/4" minimum to 3/8". But is personal preference type decision.

I have never attempted to build a cowling without the engine and prop with spinner in place on the plane. Some builders do successfully accomplish this but there have been several who have ended up having to re do their cowling when it did not match up to the measurements they carefully took. I suggest you get the prop, spinner, and engine on the plane and build your cowling around that. Mark

[Zzz]

Zane, you probably have the white finished nose bowl with the gel coat. That is the nose bowl that works fine with the MT or Hartzell spinner of 14"-14.5 diameter. There is a different nose bowl for the 13" spinner as sold by Vans. As far as gap between spinner aft edge and nose bowl - I like 1/4" minimum to 3/8". But is personal preference type decision.

I have never attempted to build a cowling without the engine and prop with spinner in place on the plane. Some builders do successfully accomplish this but there have been several who have ended up having to re do their cowling when it did not match up to the measurements they carefully took. I suggest you get the prop, spinner, and engine on the plane and build your cowling around that. Mark

Thanks Mark. I do have the gel coat white nose bowl, going to verify it's nose base diameter in a few minutes (it's stored in the attic.)

I'm not building the engine cowling without the engine in place, I just need to supply that dimension for the spinner standoff distance from the flywheel face to MT for my order. I'm assuming they supply a spacer or something.

It's not just the nose gap though, doesn't the flywheel sit recessed from the inside of the nose bowl? So the distance I'm looking for is greater than the nose gap alone. I figured this would be standard on 540 quickbuilds.

I'm at a loss because I honestly can't remember how that is assembled on the aircraft I've worked on. I need to go peep my friend's Husky or something.

[Battson]

Mike Blue has an MT on his Bearhawk, he could probably help with the measurements.

[Zzz]

After talking with Mark G, we're going to rely on the MT headquarters guys to use the spec they have on hand for the Bearhawk 4-place. I have no reason to extend the cowling from stock, so it should work fine.