Carbon cowl for the M20J

[aviatoreb]

6 minutes ago, 1001001 said:

I found a record that says my prop weight 71.3 lb, but no record of the original weight.  I imagine it has to be more that the original 2 blade. 

That's pretty heavy then.  I mean right on the tip of the nose.

[Guest]

That’s heavy compared to the original.

Clarence

[Missile=Awesome]

1 hour ago, aviatoreb said:

I think the missile and the rocket have a very very is similar size, weight and balance.  Mine was also flying very nicely when fully trimmed.  But then when I took so much weight off the nose, it is flying even much more so very nicely.

Glad you are happy.  I just don’t “feel” the weight when my plane is trimmed properly.  Of course the six vs. the four is a significant weight increase, but I honestly prefer the Mid-Body to my E and with regard to flying/landing characteristics.  I do love the appearance of your plane.  The paint and prop are stunning (my favorite Mooney visually is your bird).

[xavierde]

3 hours ago, gsxrpilot said:

I wish there was one in the works for the 252.

+1. Not sure how easy it would be to use the carbon one for the Encore that was mentioned here a few weeks ago.

[aviatoreb]

1 hour ago, Missile=Awesome said:

Glad you are happy.  I just don’t “feel” the weight when my plane is trimmed properly.  Of course the six vs. the four is a significant weight increase, but I honestly prefer the Mid-Body to my E and with regard to flying/landing characteristics.  I do love the appearance of your plane.  The paint and prop are stunning (my favorite Mooney visually is your bird).

Thank you!

[philiplane]

Carbon is electrically active, so it requires isolation from aluminum parts to prevent corrosion. That also adds weight. Cirrus uses fiberglass on their cowl, which is the best cowl ever on any small airplane. Carbon would have added cost, and complexity to prevent corrosion of fasteners that hold the cowl on. It would save no weight over fiberglass. I'm still not clear how Mooney thinks they can make a lighter cowl than the current aluminum version. I hope they can, but it doesn't seem possible. Changing a propeller on the other hand can reduce weight significantly.

Edited November 3, 2020 by philiplane

[1001001]

2 hours ago, aviatoreb said:

That's pretty heavy then.  I mean right on the tip of the nose.

Yeah, it is a big moment.

[Hank]

6 minutes ago, philiplane said:

Carbon is electrically active, so it requires isolation from aluminum parts to prevent corrosion. That also adds weight. Cirrus uses fiberglass on their cowl, which is the best cowl ever on any small airplane. Carbon would have added cost, and complexity to prevent corrosion of fasteners that hold the cowl on. It would save no weight over fiberglass. I'm still not clear how Mooney thinks they can make a lighter cowl than the current aluminum version. I hope they can, but it doesn't seem possible. Changing a propeller on the other hand can reduce weight significantly.

Don't Js have fiberglass cowls, not aluminum?

What are the Ultra cowls made of?

[kortopates]

47 minutes ago, xavierde said:

+1. Not sure how easy it would be to use the carbon one for the Encore that was mentioned here a few weeks ago.

For 252's, Its as easy as spending the $12K+ for one! That price was from 5-6+ years ago, no idea what the price tag today is. 

I am just thankful they didn't make it required part of the drawing to go from the 252 to Encore conversion. 

Edited November 3, 2020 by kortopates

[philiplane]

10 minutes ago, Hank said:

Don't Js have fiberglass cowls, not aluminum?

What are the Ultra cowls made of?

Yes, the J's are fiberglass versus the F and earlier aluminum cowls. Carbon doesn't really offer any weight savings over the fiberglass cowl, without significant changes to the overall design. Just putting carbon fiber into the current fiberglass molds won't change much. Not for the price, which will be higher than fiberglass. Carbon costs much more, is harder to handle, has a shorter shelf life, and requires post treatment to prevent corrosion of the fasteners and where it mates with the aluminum airframe. 

[1001001]

17 minutes ago, Hank said:

Don't Js have fiberglass cowls, not aluminum?

What are the Ultra cowls made of?

I'm pretty sure my J has a fiberglass cowl.

[carusoam]

The long body cowls have gone to carbon...

The cowl parts are really big on the long body...

We could probably fit Clarence’s flat eight under there...  

When it comes to WnB... a couple of pounds off the nose would be great...

If you have Charlie weights, you would see an immediate benefit of lighter hardware up front...

Aluminum is not the best material for the cowl...

yes, sure it is a great bang for the buck when it  comes to strength and lightness... but it doesn’t form very curvy parts...

Aero requires curvy... even my 65C’s cowl didn’t fare very well over the years as it had a tendency to crack along a deep forming line on the nose...

PP thoughts only, not a mechanic...

Best regards,

-a-

[xcrmckenna]

I’m looking forward to the carbon cowling for my J. I’ve been talking to Mike Patey for years trying to get him to fabricate me one.


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[mikefox]

Hopefully the carbon cowl for the J can fix the annoying modal (flexural) vibration issue which cracks the paint on the top cowl!

[AerostarDriver]

Some what interestingly many of the J cowls I have repaired have had carbon in them in key places. I believe the motivation for moving to carbon has to do with stiffing the cowls up rather the the weight savings. Lopresti said it best when they designed there 201 cowl. "We have beefed up key areas like the cowl flap attach points to prevent them from falling off." Other manufactures solve this by adding a nomex honeycomb or simple foam. A good example are the Vans RV cowls which use both foam and nomex honeycomb in hot areas.

[rbridges]

21 hours ago, philiplane said:

Yes, the J's are fiberglass versus the F and earlier aluminum cowls. Carbon doesn't really offer any weight savings over the fiberglass cowl, without significant changes to the overall design. Just putting carbon fiber into the current fiberglass molds won't change much. Not for the price, which will be higher than fiberglass. Carbon costs much more, is harder to handle, has a shorter shelf life, and requires post treatment to prevent corrosion of the fasteners and where it mates with the aluminum airframe. 

That makes sense about the weight. My J cowl doesn't seem to carry much heft. Are the cowls for long bodies made of aluminum?

[Tim Jodice]

23 hours ago, carusoam said:

The cowl parts are really big on the long body...

We could probably fit Clarence’s flat eight under there...  

PP thoughts only, not a mechanic...

Best regards,

-a-

How much heavier would a 720 naturally aspirated with a composite prop be compared to a 550 turbo with an aluminum prop?

 

 

[carusoam]

3 hours ago, rbridges said:

 Are the cowls for long bodies made of aluminum?

Fiberglass similar to the M20Js....

With fancy smooth air inlets, and perfectly sized air outlets around the exhaust pipes...  No cowl flaps required...

Best regards,

-a-

[gacoon]

6 hours ago, mikefox said:

Hopefully the carbon cowl for the J can fix the annoying modal (flexural) vibration issue which cracks the paint on the top cowl!

+1 on that one

[jonhop]

How about infinitely adjustable and measurable cowl flaps on the J. Sure I can trail the cowl flaps but tracking engine performance with a monitor is significantly tougher with cowl flaps that are open, closed, or in trail--which is a completely random setting. I get lots of numbers on my engine monitor. It would be nice to have an infinitely adjustable cowl flap setting that's measurable, that lets me further fly by the numbers. They exist on more modern Mooney's...

[carusoam]

How about copying the airflow design of the O’s cowl, and apply it to the J cowl, that was pretty good for its day...

The O has great CHT control without any cowl flaps...

Deep LOP in the depth of winter, CHTs may dip below 320°F if not paying attention...

Thinking out loud...

If you get a chance to update... go for all the donuts...  

Best regards,

-a-

[jetdriven]

7 hours ago, mikefox said:

Hopefully the carbon cowl for the J can fix the annoying modal (flexural) vibration issue which cracks the paint on the top cowl!

carbon fiber reinforcement fixes that.  The carbon cowl will weight about 60% of the fiberglass version.

hopefully they optimize the inlets and outlets. Because theyre both about twice as big as they need to be.

[Tim Jodice]

6 hours ago, jetdriven said:

hopefully they optimize the inlets and outlets. Because theyre both about twice as big as they need to be.

How do you know that? Not being a smart ass I really don't know. I have always wondered how they cool 310 HP in an Ovation with smaller holes no cowl flaps than 200HP in a J with bigger holes and cowl flaps. 

If they did both on a new cowling that would be great. weight loss and lower drag. 

[bfreelove]

The Ovation cowling is the best design I'm aware of for any certified aircraft (IMHO).  The key is in the inlet ducting, sizing, and exit "extractors".  The inlet ducts look particularly optimized for the engine.  The designer was clearly well versed in the state of the art.  I haven't measured the upper plenum pressure recovery yet (would like to at some point), but I would guess it will be quite high compared to most cowls. I have the Ovation cowl on my M20L and with a good set of baffle seals and careful use of silicon to seal any leaks the cooling is actually too much.  I have to run the oil cooler winterization plate year round and most of the CHTs run in the low 300s high 200s depending on OAT and altitude. 

[Tim Jodice]

How is the Lopresti cowling for J models? Is it heavy? does it have cowling flaps? Do you gain speed? Does it do a good job cooling the engine?