Weight and Balance Possible Issue

I am building an RV7 tail dragger with tip up canopy. I have a Titan IOX370 (non counterweighted) being built that will be spinning a constant speed prop. I am going with a single battery (3lb lithium on the firewall), dual alternator setup (the backup alternator being the lightweight SD-8). I am also installing a single G3X touch with the GTR23ES transponder.

I have heard that the RV7's are usually a little tail heavy. My concern is I have a lightweight battery up front, minimal avionics weight, and I want to install the GTR23ES transponder just aft of the baggage compartment. I would like to do this because it will free up a lot of space behind the panel for future upgrades (second G3X touch, IFR nav, ADS-B) and the difficulty of properly securing it behind the panel. What do you guys think? Should I just somehow figure out a way to install it behind the panel, or will I be all right?

Thanks!

The -7A and -9A's tend to be tail heavy, not the taildraggers. (It has something to do with the mains being behind the CG.)

It is much easier to add weight than take it out. Keep building lightness in, you can always adjust the CG later.

W&B calculator???

You might do a search on here, or Google, I'm pretty sure there are a few spreadsheets (excel or similar) that other builders have created which would allow you to play around with all these configurations.
Once I had a little one modified for my plane (already built) it was interesting to add baggage in it's 'real' locations, like behind the seats, or at the back of the baggage area, (where jugs of water always tend to slide when climbing out!)
a good exercise to be sure....the good news? I find it almost impossible to loads outside limits.

N941WR said:

The -7A and -9A's tend to be tail heavy, not the taildraggers. (It has something to do with the mains being behind the CG.)

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I'm not sure that's right, Bill.

My 7A empty CG is as way far forward. It is impossible for my GC to go out the back if I follow 100lb baggage limit.

It was my understanding that 7s with fixed pitch were the tail heavy ones.
Adding a nose gear and a CS prop brings the CG a long way forward.

Bill, Bill is right! hahaha

The fixed pitch 7's are the tail heaviest.

As a datapoint, my 7 came in at 1109 lbs.

I am AT THE FORWARD LIMIT when empty. Everything I add, goes aft. I have a full 100 lbs. available in the baggage compartment.

I am a parallel valve, constant speed, G3X with electronic ignition boxes mounted on the firewall.

I hope this helps.

CJ

Sounds like I should just leave it in the tail. Probably won't be an issue since I'm putting in a cs prop. Thanks everyone!

I have my 23ES mounted on the baggage bulkhead, good location and works perfect with the short coax between it and the antenna mounted about a foot aft of it.

Walt said:

I have my 23ES mounted on the baggage bulkhead, good location and works perfect with the short coax between it and the antenna mounted about a foot aft of it.

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Darn, wish I would have thought of that before I drilled and mounted my rack to the bottom skin!!!

Depends on the prop

carrollcw said:

Sounds like I should just leave it in the tail. Probably won't be an issue since I'm putting in a cs prop. Thanks everyone!

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I have a 7 with an IO-360 and MT three blade. The prop is still 20+ lbs lighter than the metal CS.

With a finished weight of 1080, I am CG limited to 75 lbs in the baggage compartment! Do the math with your prop of choice. It has the longest ARM to consider.