RV-6A weight & balance

[chriscencula]

I'm building an RV-6A & would like to know if they are usually more tail-heavy or nose-heavy with a CS prop... I've got the old 0.016" rudder/elevator skins.
Firewall forward will be similar to the RV7 (battery in front of the F/W).

I'm asking because I've been thinking about 'building in' the option for a RV6-conversion at a later date & wondering about the extra weight of including the tailwheel weldment. An alternative would be to design a similar weldment that can be installed (bolted in) afterwards, but this would likely have to be two pieces instead of the one that attaches to both (612 & 611) bulkheads so it could be put in place without disassembling the tail.

Even if I don't do anything 'special' in terms of 6A-to-6 conversion options, it would be nice to have some idea ahead of time if the plane will likely be nose or tail-heavy with the C/S speed prop.

Thanks,
Chris

 

[gasman]

The C/S prop will make it fwd cg (nose heavy). That won"t be a problem. Go ahead and install the 6 conversion. I have it on mine and with a Sensenich fp, the plane flies just great, I just can't take the kitchen sink with me......... but it is a nice balanced A/C.

 

[curtis]

I was looking at putting the tailwheel weldment in my 6A and was told by Van's that I would loose approx 20 lbs of baggage. This info was based off of one of their demonstrator aircraft that they called Ole blue.

 

[gasman]

I was looking at putting the tailwheel weldment in my 6A and was told by Van's that I would loose approx 20 lbs of baggage. This info was based off of one of their demonstrator aircraft that they called Ole blue.

This is true, due to weight and balance. But when a constant speed prop is installed, you can carry more baggage and still be in balance. And depending on the amount of fuel you have on board, you might exceed the published gross weight unless it has been extended.

That IS WHY I can't bring the KITCHEN SINK........ see above post......

 

[Snowflake]

I'm asking because I've been thinking about 'building in' the option for a RV6-conversion at a later date & wondering about the extra weight of including the tailwheel weldment.

If you're already thinking about the tailwheel now, and you're not even finished the airplane, why not just build the tailwheel now and save yourself the conversion (and the added weight for it) later? Tailwheel checkouts are not that difficult.

 

[L.Adamson]

If you're already thinking about the tailwheel now, and you're not even finished the airplane, why not just build the tailwheel now and save yourself the conversion (and the added weight for it) later? Tailwheel checkouts are not that difficult.

Maybe he is like me. I went with the advantages of nosewheel for the 6A, but preferred taildraggers for tandem airplanes. I also still believe that 6A's still look better on the ground. Just more substantial. Guess I was comparing a tri-gear Glasair to it's taildragger model. Believe it or not...............that's what made my final decision after months of thinking about it. If I ever get another plane, it will be a tail dragger bush plane (Cub clone). Yet I prefer seeing what's right in front of me, with the 6A, and a bit of an advantage with cross winds.. I don't try to "play" bush plane with RV's...

L.Adamson --- RV6A

 

[chriscencula]

RV-6A weight & balance w/CS prop & "tail wheel option"

I haven't calculated the weight x moment arm yet to see how the weldment alone would equate to baggage weight...

Seems like it *could* be as much as 20lbs baggage if it is ~2lbs (probably less) and 10x farther 'back' (from ~1/3 chord) than the baggage compartment...

My *guess* is that it wouldn't be quite that high. Will have to calculate the weight of the weldment (or an equivalent)... If the design of the weldment were changed to allow installation/removal, then one wouldn't have to 'pay' the weight penalty if not using it, just need to make sure it has been designed & match drilled for later installation/removal...

With the tailwheel installed one could imagine the weight being substantially higher... Wonder if anyone knows the weight of the T/W assembly (with/without mount)?

Is the tube/rod that 'plugs into' the T/W weldment a 'solid' rod, or is it hollow?

I'm a low time PP that hasn't flown as PIC in a long time. When the time nears, I'll get *plenty* of instruction & then probably a *lot* more in an RV-6x or RV-7x with someone who experienced in RV instruction...
That said, I'm still pretty sure I'll want the 6A, but maybe *someday* I'd like to switch to a '6' without completely starting over... I've been told that at someone did a custom engine mount that had provisions for *both* the nosewheel and the main gear... Even though I won't be a the 'engine mount' stage for some time, it's got me thinking...

Thanks,
Chris

P.S.

 

[jetjok]

With the tailwheel installed one could imagine the weight being substantially higher... Wonder if anyone knows the weight of the T/W assembly (with/without mount)?

Chris,
I think a more valid comparison would be;
1. What is the weight of the engine/gear mount for the TW -6 vs the mount for the -6A?
2. Then subtract the weight of the main gear weldments and hardware for the
-6A.

That would answer your question on a basis of weight. I believe that Van's statement of losing 20 lbs of baggage is a CG issue, not an useful load consideration. Adding a C/S prop would definitely move the CG forward and would more than negate the aft moment of the TW brackets.
I will join some others in stating that IF you think you may want to have a -6, then build it that way. Once you get it flying, you will certainly not want to tear it down to change over!
If you read the other threads on the ad infinitum discussions of TW vs NW, you will see that I am big proponent of the TW, just as Mr. Adamson is a proponent of the NW. I believe that both of us do agree that every builder should build the plane as they want it in the beginning and 10 years from now.
Good luck!