What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Any new solutions for tail heavy RV-7's

S

Spindrift

Well Known Member
Hi all,

I've done several searches and read old threads here and in the archives, and at this point I'm leaning toward a heavier spacer for my RV-7 with a Catto 3-blade and IO-360 that is definitely tail heavy. I'm headed to Oshkosh next weekend and its looking like my baggage capacity is pretty limited with 400 lbs of pilot and passenger unless I come up with a quick solution. Most of the threads are a few years old or more, so I thought I'd repost the question to see what people have come up with more recently.

Thanks,
 
One approach

I switched from a Sensenich to a Catto this year, difference in weight is 24 Lbs, I added a sabre 7 inch 14 Lb crush plate to help make up the difference. I already had a landoll harmonic balancer (approx 12 Lbs) installed to help the W&B with the sensenich and could carry 100 Lbs of baggage with min fuel and 2 FAA standard weight pilots. I just re ran the numbers and with my typical 2 up pilot/pax configuration (317 Lbs) and min fuel my baggage is limited to 95 Lbs due to the loss of the extra 10 Lbs from the nose.
Interestingly I weighed my flight bag and my RV travel kit (tools, spare oil, plugs, tie downs etc) this weekend prior to osh and they added up to 46.6 Lbs!!
I would recommend the sabre crush plate and they are great people to work with. They do have a heavier 8 inch crush plate available also.
 
Yes, to all the above.

It is a fact with a light weight aft CG airplane, you can take off in CG limits and be aft of the aft limit for landing. Be sure to run the numbers with arrival fuel.

I can carry 100# of baggage but am limited to a max of 230# in the pilot seats with fuel fuel, and will be about .25" forward of the aft limit for landing at OSH.
 
Saber crush plate it is

Thanks for the tips. Spoke to Craig Catto this morning, and he recommended talking to Sam at Saber Manufacturing, which I did. Sam said the best bang for the buck is a 8" diameter, 1 3/8" thick, 19lb steel crush plate with longer bolts.

My other plan is to figure out a way to strap something heavy (i.e. oxygen or tiedowns) to the center cover in front of the fuel pump instead of in back.

I'll post an update once I get it installed and re-weighed later this week.

Thanks,
 
small differences

Couple of things I do to help the situation, I have the bison RV bag that fits over the flap cross shaft, I load it with the heavy stuff forward which is almost under the seat . I also use stuff the fly-tie bag and it fits forward of the same flap cross shaft under the other seat. Moves some weight a bit forward and leaves space in the baggage compartment for lighter but bulky stuff. On reflection I should have bought the 8 inch crush plate from Sam as the extra 5 Lbs on the nose would make a noticeable difference.
 
Yet another reason to sing the advantages of a tail dragger!

You have about 15" of clear area either side of the fuel selector and fuse sidewall just in front of the thin metal panels covering the fuel plumbing. I made long brackets that have slots at either end for passage of tie down straps. The brackets themselves are held in place by the two screws through the panels into the forward spar bracket upon which they rest. To these, you can lash down all manner of objects, like tents, water bottles, etc., that otherwise would wind up in the baggage area. Your knees pass over the top of these stores so no discomfort.

Every little bit helps.

John Siebold
 
Pictures

Hi John,

I like the idea. Do you have pictures by chance? I attached a fire extinguisher in that location on the left side, but it came with the bracket so I just had to add a nutplate.

Mike, wouldn't that require more gas, which would just push the CG back to where it started.:rolleyes:
 
David-aviator said:
Or go with a Mccauley, they're heavier yet. :)

I like a light weight airplane. Dealing with an aft CG limit usually is no big deal. Plan the trip and load and it all works out ok.
Click to expand...

My plane does balance out nicely with the Hartzell. Can't beat a
C/S for the higher altitude airports that I fly from. Of course, considering the engine/prop combo you replaced............I'd be thinking lighter too! :D

L.Adamson --- RV6A
 
Have you looked in the Landoll Harmonic Balancer?

Not as heavy as the Saber plate but it will also dampen out some vibration.

I have been using one on my -4 since '03 and have been very happy with it.


Glenn Wilkinson
 
glenn654 said:
Have you looked in the Landoll Harmonic Balancer?
Click to expand...

For now I'm just going with the Saber plate. Post Osh I may explore the harmonic balancer. Just have to spread out the cost a bit!

Got a bracket fabricated tonight to allow strapping the tiedowns and tools below the passengers legs, so that should help a bit as well.

Thanks,
 
RV7ator said:
Yet another reason to sing the advantages of a tail dragger!

You have about 15" of clear area either side of the fuel selector and fuse sidewall just in front of the thin metal panels covering the fuel plumbing. I made long brackets that have slots at either end for passage of tie down straps. The brackets themselves are held in place by the two screws through the panels into the forward spar bracket upon which they rest. To these, you can lash down all manner of objects, like tents, water bottles, etc., that otherwise would wind up in the baggage area. Your knees pass over the top of these stores so no discomfort.

Every little bit helps.

John Siebold
Click to expand...

I do the same thing. Usually on flights where I see a CG issue in the making, I'll put my 10# tool and tiedown bag on one side of the fuel valve and a gym bag or equivalent to the other side. That moves 15-20 pounds (total) from the baggage compartment to a station adjacent to the fuel tanks.

Also, if I know I'm nearing the aft limit, I'll leave the right control stick out and have my passenger grab a bag out of the back of the airplane and put it in his/her lap for the landing.

These things make a big difference and IMO the minor inconvenience is less of a sacrifice than spending $$ and useful load on a flywheel weight or a harmonic balancer.
 
You must log in or register to reply here.
Back
Top