HIIFLY

HIIFLY

Well Known Member
I have an RV-6 with a a Io-320 Sensenech fixed pitch prop , I weigh 230 lbs and with a 185 lb passenger it is at th rear of the C/G limit I am sure of . I would like to add nose weight , maybe a 11 lb weight ring on the starter ring gear like I had on my 8 for awhile , but I need more ! So my question is , what does this group think of adding Lead Shot in an epoxie slury inside of the front upper and lower cowling air inlets , like 2.5 lbs in each of the four spaces ? I wonder about the stress on the cowl fasteners , the cowl is very light but very strong I don't think that it would cause a problem , but would like any input + or - , or has anyone done this yet ??? . Thanks , Joe
 
W&B

I'd recheck the W&B before doing anything. I've got similarly set up -6 and don't get near aft datum with that loading plus 50# baggage. To the original question, I'm not an engineer, but cowl inlet weights strike me as a bad idea. Standard weight starter, landoll ring, bigger battery can all add weight without compromising in other areas.
 
Starters

One local builder dumped his lightweight starter and went to the old certified boat anchor version to help a similar W&B problem.
 
az_gila said:
One local builder dumped his lightweight starter and went to the old certified boat anchor version to help a similar W&B problem.
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I'll second this. I went with an old starter to keep weight on the nose and felt bad when the starter died and I had to replace it with a lightweight version. I just put a 19lb crush plate on my 6A and it made several positive improvements. First, it moved my CG a full inch forward. Second, it allowed me to smoothly idle much lower and last, it helped to smooth out the engine vibrations at lower RPMs. The crush plate is steel and came from Sabre.

I really would not want to put weight on cowl. I think that you are just asking for problems. Look at how many people report failure of their hinge mounts at just the stock weight, which is really quite low. A couple of pounds at that much arm is just asking for trouble in my opinion.

Larry
 
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Wow !

Wow 19 lb crush plate ! That would do it ! I do not want to give up the torque of the lint starter . What does it cost to have Saber make it and the longer bolts that are required ????
 
I used a Prestolite starter for the first 12-13 years I flew my airplane. The extra weight really helped the CG. When it died, I replaced it with a Skytec plus a 9 lb bolt-on flywheel ring. I also considered casting a lead weight to bolt to an unused boss on the bottom of my O-320 case. I'd do that before I added weight (and stress) to the cowl.
 
HIIFLY said:
Wow 19 lb crush plate ! That would do it ! I do not want to give up the torque of the lint starter . What does it cost to have Saber make it and the longer bolts that are required ????
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I am not sure what they run new. I bought mine for under $200 from a fellow VAF member. I bought 7/16" Grade 8 bolts from McMaster and drilled the heads myself. Cost was under $25 if I remember. A bolt set from Saber was over $75 (grade 9).

Larry
 
HIIFLY said:
I do not want to give up the torque of the lint starter
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I had planned to put another old starter on until I used the skytech. I really like the extra cranking RPM and lower battery drain. After the last kickback event, I'll do anything to avoid it and the possible breakage of my ring gear.

Larry
 
Heavy crush plate!

If you change prop from Sensenich metal to Catto, you need up to 20 lbs of crush plate, made by Sabre.

+ you cant go more forward


May be go with a heavier/bigger battery and or starter. Not that much forward, but maybe helpful to.
 
Thanks for input .

FYI , my RV-6 has a Odssey PC925 Battery inside of Firewall , I don't want to move it for little gain. I have a Skytec starter and a light alternator . I don't want to give them up for the heavier old stuff. A Hartzell Prop would be Great but , I don't want to spend the money ! I have a Senesenich metal prop that works really well for my mission . Finding a weight ring for the ring gear well, is difficult . Having one made , I haven't tried that yet . And the Crush plate which sounds very good and I can't see why it can't be used on the metal prop so I am considering it . The lead shot is the cowl was just my home builder Brain working on how to help the situation . Tail heavy . Also although I am Not a Test Pilot I have 6 First flights in different Experimentals and have listened to all the Old timers who have mentored me through the years . Here is what I know ,
When you are slowing down and approaching the stall speed , if the nose does Not want to drop down and the control stick gets Heavier , you are are getting close to a tail heavy condition . When I do this in my 6 with a 185 passenger and half tanks no baggage , the nose wants to stay Up and my control stick feels neutral or no back or forward pull . No stall was attempted just a mush and I pushed nose down and added power and flew out of it . Solo it flys Great !
I know I shuld just loose 40 lbs and it would be better , but at 67 it ain't happening ! LOL . Thanks everyone , Joe
 
What was the end?

Sometimes I revive old threads to see if a conclusion was ever reached...I'm firmly of the opinion that no situation is completely unique, so I'd love to know your solution to your light nose (sounds better than heavy tail)

I have a similarly equipped RV except with an even lighter prop after I removed th sensenich. Math says with your original layout that I'd be ok taking off with full fuel, but as I burned fuel, I'd see my cg approaching rear max quickly, and with two onboard, my landing quality goes down quickly, and effort required rises dramatically.

I'm thinking of fixing casting some of my reloading ingots into a nice large block or two (I melt them down from wheel weights and store them as 1 lb ingots) and try to figure out where I could affix them to the block...

My numbers indicate that as little as 10lbs could make a huge difference in my handling. It looks like I got lucky with my crush plate and setup from sabre and everything is nicely balanced; I hate to mess with that now!

Anybody ever weighted the tip of a spinner? I wonder if a guy could shape lead and ever get it to balance?

Just reading and thinking...
 
punkin said:
Sometimes I revive old threads to see if a conclusion was ever reached...I'm firmly of the opinion that no situation is completely unique, so I'd love to know your solution to your light nose (sounds better than heavy tail)

I have a similarly equipped RV except with an even lighter prop after I removed th sensenich. Math says with your original layout that I'd be ok taking off with full fuel, but as I burned fuel, I'd see my cg approaching rear max quickly, and with two onboard, my landing quality goes down quickly, and effort required rises dramatically.

I'm thinking of fixing casting some of my reloading ingots into a nice large block or two (I melt them down from wheel weights and store them as 1 lb ingots) and try to figure out where I could affix them to the block...

My numbers indicate that as little as 10lbs could make a huge difference in my handling. It looks like I got lucky with my crush plate and setup from sabre and everything is nicely balanced; I hate to mess with that now!

Anybody ever weighted the tip of a spinner? I wonder if a guy could shape lead and ever get it to balance?

Just reading and thinking...
Click to expand...

Check the underside of your engine case for an unused boss. Bolt a weight there if you have that boss.

I would not consider adding weight to a spinner. Spinners occasionally break, and I would not want to deal with the vibration of a heavy spinner if it self destructed.

You might also look at using big hose clamps to clamp lead sheet around a lightweight starter.

In general, it is easier to add weight than remove it!
 
Didn't think of that...

I think the RC guys weight their spinners, but they've got a lot less to lose and a lot less weight! You're right, if a spinner did come apart, 10lbs to toss around or get out of center could get pretty hairy fast!

I'll take a peek and see what I can find...I bet there's lots of places I can gain weight fast...
 
Nose weight

I had Saber machine make me a "22lb. Prop extension " . That did the Trick !
A lighter 18 lb. one would be my first choice . But he had this one on the shelf so I took it . Not sorry at all . I think it cost $ 400.00 plus shipping ??? Don't quote me on that . BTW I still weigh 230 lbs. !:D
 
I just ordered the 20# plate for my -7A with Catto 3 blade, NLE. Also have Skytech NL starter and Plane Power Alt. PC-680 on right side of FW. If the 20# plate turns out to be too heavy (not likely from what I've read), I can swap out the battery for an Earth-X.
 
HIIFLY said:
I had Saber machine make me a "22lb. Prop extension " . That did the Trick !
A lighter 18 lb. one would be my first choice . But he had this one on the shelf so I took it . Not sorry at all . I think it cost $ 400.00 plus shipping ??? Don't quote me on that . BTW I still weigh 230 lbs. !:D
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Cool. I had Saber make me a 10lb plate and 7lb extension, looks like I should have gone heavier. Unfortunately, I didn't have enough time with the Sensenich prop on previously to realize how far aft the CG was getting (even with the heavier prop) as fuel level dropped.

I'll probably come up with a clever lead tube or something to get some more weight forward.

My prop balanced SO well (accidently-ish) after install, I hate to try to add a heavier plate and then fight balance issues!
 
punkin said:
Cool. I had Saber make me a 10lb plate and 7lb extension, looks like I should have gone heavier. Unfortunately, I didn't have enough time with the Sensenich prop on previously to realize how far aft the CG was getting (even with the heavier prop) as fuel level dropped.

I'll probably come up with a clever lead tube or something to get some more weight forward.

My prop balanced SO well (accidently-ish) after install, I hate to try to add a heavier plate and then fight balance issues!
Click to expand...

Though expensive, a tungsten bar bolted up front would be the most compact solution, IMO. Gulfstream aircraft use them for elevator counterweights. They get replaced on occasion for corrosion.
 
punkin said:
Cool. I had Saber make me a 10lb plate and 7lb extension, looks like I should have gone heavier. Unfortunately, I didn't have enough time with the Sensenich prop on previously to realize how far aft the CG was getting (even with the heavier prop) as fuel level dropped.

I'll probably come up with a clever lead tube or something to get some more weight forward.

My prop balanced SO well (accidently-ish) after install, I hate to try to add a heavier plate and then fight balance issues!
Click to expand...

Why don't you replace your 7 pound prop extension with a 15 or 20 pound prop extension by saber, I didn't notice any vibrations by changing my prop extension, I think this would be the quickest and easiest solution .
 
You are correct, I'll have to explore that! I'm pleased that you didn't have any balancing issues either when you put it together. I am just really happy with the prop balance right now and would hate to start a battle!

Thanks!
 
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