Air Command Rebuild / Advice Needed

[bhalls]

Hi All,

I'm doing a "from the ground up" rebuild of my AC 532 to CLT, including the 10 inch taller "Superthruster" Mast.

My current prop is 60" diamater warp drive and my blades are 23' Skywheels. The new taller mast will allow me the option of upgrading in the future to to 25' blades and/or a 68" prop. (If I were buying a new AC582 machine today (http://www.aircommand.com/commander%20582.htm), it would come standard with both the larger prop and rotors).

My local airport is is 5020' high with mountains all around, so the density altitude for most of my flying will be quite high, i.e, performance matters.

So, my question: To install the 68" prop later (should I determine it to be necessary) means that I would have to raise the engine 4" above what would be needed for my current 60" prop. Seems to me that it makes sense to raise the engine now, as doing it later would mean new engine support tubes, a new pre-rotator cable, and an unwanted hole left over in my mast, at the very least. Any major concerns or reasons as to why I shouldn't just mount the engine 4" higher to begin with?

Also, assuming a 600/650 lb AUW my disk loading for my 23' blades will be 1.44/1.56 respectively. For the 25' blades the corresponding disk loading would be 1.22/1.32. These seem to be within the norms for acceptable ranges I've found on the forum. Any concerns here?

Thanks in advance for your help!

Brent Halls
Morgan, Utah

[automan1223]

First time. is always the best time to do it right.

at your D.A it would pay to go bigger with rotor and prop.

Do it right the first time as you can always put that power/lift back in your pocket, but you cannot take it out if you aint got it.

Jonathan

[bhalls]

Thanks, Jonathan.

My intention is to originally use my current prop and rotors. The idea is to find out how well they will perform, while maintaining an upgrade path in the future should I feel the performance increases are necessary for flying here.

That's why I'm asking about raising the engine mount now instead of later. The question is whether there is any serious reason to not mount the engine 4 inches higher now, in order to allow for the possibility of the larger prop in the future.

Brent

[automan1223]

Putting things where they might be soon after completion is only smart, time saving. We have many builders that did stuff and had to back track or are in the process of "reworking' rebuilding, or repowering their machine to make things the way it should have been in the first place.

Take it from me. I did things the long and hard way. I got a good education along the way but I could have been flying years ago....... Stuff happens.

Jonathan

[Udi]

I flew my old CLT Air Command from 5000 ft with a 60" prop and 24 ft DWs. My all up weight was 550 lbs and I got good performance.

One word of caution - When you raise the engine by 4", you are moving the prop thrust line 4" up relative to the CG. I don't think that will be detrimental, because my own AC, according to some flight testing I did, had actually a LTL. If I were you I would raise the engine 4", and then do a double hang test to determine thrust line location vs. CG. You may compensate, if necessary, with the stab.

Udi

[Rehan K.Janjua]

Hello Brent
This is all good advice from wonderful people.
Right on the money. Thank you all.
I have a A/C 582 single HTL 25' sky wheels, 68" warp. Even flys from 10,000 ft D.A.
Love my Air Command.
Best Wishes and good luck.
Rehan

[bhalls]

Thanks, guys. This helps a lot.

Udi: I remember seeing your Air Command when you had it for sale on ebay. I was impressed with what a beautiful job you had done. Do you still have pictures of it that you could share with me? They might give me some hints and ideas. At the time I snagged your sale page off of ebay, just for the pictures, but I didn't think to snag the individual pictures. Later, you must have pulled the pictures from the website the page linked to, since when I went back to the page the pictures links were broken.

I've also read your comments since then about how upgrading an AC with a CLT kit isn't necessarily as simple as installing the kit. I too have found many "little" things along the way that in order to be satisfied, I had to check out and in many cases replace. For that reason, this project is taking me longer than originally anticipated, and amounts to rebuilding my machine from a "pile of parts", just as if I were doing a new one, only more so! However, when I'm done, I'll have a machine I have confidence in, and will have gained some of that "education" that Jonathan refers to.

In you have some pix you could email to me, that would be great. I'll PM you via the forum with my email address. Please watch for it.

Rehan: Good to know about the performance envelope including 10,000 DA's. The mountains around my home go to 10000 feet, and although I don't expect to see the tops of them in my Gyro (at least not from above! :),) there is a lot of beautiful country nearby in between!

Brent