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Opinions, please: W&B w/EXP119

SabreFlyr

Well Known Member
Sponsor
How risky would it be for me to use the EXP119 engine (about 10 pounds lighter?) as far as aft CG issues are concerned?

For almost as long as I’ve been building my -14, I’ve been concerned about ending up with an aft CG issue. I had been planning on dual alternators because I was also planning on a full SDS EFII system. If I CAN switch to the EXP119 (engine and finishing kit already ordered), I wouldn’t have a second alternator and would probably switch back to an emag system. That would allow me to use a much simpler electrical system (something that I would greatly appreciate). I’m also concerned that my primer in the empennage and tailcone was applied too heavily (definitely not just a misting). I would also like to use an EarthX battery but that, of course, wouldn’t be a necessity.
 
How risky would it be for me to use the EXP119 engine (about 10 pounds lighter?) as far as aft CG issues are concerned?

For almost as long as I’ve been building my -14, I’ve been concerned about ending up with an aft CG issue. I had been planning on dual alternators because I was also planning on a full SDS EFII system. If I CAN switch to the EXP119 (engine and finishing kit already ordered), I wouldn’t have a second alternator and would probably switch back to an emag system. That would allow me to use a much simpler electrical system (something that I would greatly appreciate). I’m also concerned that my primer in the empennage and tailcone was applied too heavily (definitely not just a misting). I would also like to use an EarthX battery but that, of course, wouldn’t be a necessity.

A far bigger influence on empty C.G. (compared to all of the things you mentioned), is what prop. you chose to use.

If the blended airfoil Hartzel is used (like is on the prototype/demonstrator and used for all of the performance testing), there should be no issues with the resultant empty C.G. If you chose to use a composite prop., then the C.G. would be less than ideal.
 
I used the Hartzell composite prop on my RV-14A and my cg is near the forward limit with full fuel and just me (172#). I also have the standard PC680 battery and a stand-by alternator, both of which move the cg forward. I would think the lighter engine and lack of 2nd alternator (not sure where it could be installed) would improve the cg situation, although I don’t know if you would end up with a greater potential for reaching the aft cg limit - which would be very difficult for me.
 
A far bigger influence on empty C.G. (compared to all of the things you mentioned), is what prop. you chose to use.

Yup, shoulda mentioned that the 72" Hartzell BA is sitting in my garage. Just got an email that my finish kit will crate next week. Can we hold up just a bit? :) (Email and phone message submitted; awaiting reply.)
 
I'm running a 2 blade composite WW 74HRT and stock battery, no 2nd alternator and have never had an aft C/G problem. For an extreme example, with 5 gallons of remaining fuel, 200lb pilot and 250lb passenger, I can still put 89lbs in the baggage area and be within limits. Yes, I can't put the full 100lbs in baggage but this is also an extreme example that I can't ever envision taking place with my usage.
 
Scott, Mark, Chris, thank you all. Starting to look like i'm gonna do this. Just a couple of more questions to get answered. More AMUs but, by having to cancel my current finish kit order and place a new one, Van's will actually be saving me a few of those AMUs (actually, a bit more than 1/2 AMU) with their new military discount. :)
 
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