the Wasp

My Feedback: (1)

that would be vary easy to do on a Mill/Drill machine, in fact you could make a jig from hard wood for the case. so the case would mount to the jig just like a plane's engine mount, you could mount the jig to the table and level it by milling it, then mount the case to the jig and shim the case to level it then mill the case, it would be easy,

humm you could do all that on the lathe, in fact it would be better to do it on a lathe than to use an end mill, you could mount a jig to an independent jaw plate thew the back of the plate

I remember when I ran RC boats I increased the compression on a Zenoah 23, I did it on the lathe, but it was so long ago I can not remember how I went about holding the cylinder, I must have used the independent jaw plate..

you know the engine to do would be the FA91

Jim

SrTelemaster150

It was better before Photobucket screwed the pooch and held all of my pictures for ransom.

For all practical purposes, using the FA-150 case proved problematic. Better and much simpler to mill the FA-180 case .032".

Captcrunch44

Rudolph Hart

If you like flying at head height or lower quite a lot there is the occasional penalty to pay.The fa220 flew through the top of a wait a while bush and left it's aeroplane behind,so it's on the bench in the sin bin.I hope you finished the 7x57mm off they make a beautiful rifle.Be a damn shame if you had to give up that smelly muzzle loading gig,used a 45/70 black powder rig once on a calm day,fired and was surrounded by a thick cloud of blue smoke couldn't see fa.They must have been brave shooting dangerous game at close quarters back in the day before smokeless powder was common.

Jesse Open

I ordered a crank, should be at the hobby shop this week. I will see which case works best, I have several 120, 150 and 180 cases. Then it is time to measure. I made the 150 shim template and cut several shims many years ago to drop the CR on my first 150. Still have the stuff on hand. Did the 65 and 80 as well.
Planned to photo the conversion progress and show it on a photo page. I have a 150 Glow on my Rascal 110 right now. Had planned on going to a 120 but this engine may be just right.

Captcrunch44

Glowgeek

Both my 82's vibrate something fierce! Two of my Sbach cowl screws were loose and one was missing after just a couple of flights. This after using thin CA to harden the holes in the ply several times. Last night I drilled the holes to 1/8" and epoxied in the yellow inner nyrod pieces and cut washers from tygon fuel tubing to serve as damping washers for the screws. I've had good results before doing that but man, the vibes are out of control. The prop and spinner are in perfect balance and all fasteners have been double checked. Tuning is not overly rich and bearings are new.

Has anyone had good results by "clocking" a slightly out of balance prop to reduce engine vibes?

Hobbsy

My Feedback: (102)

I did that with a BTE Flyin King, I had removed a Fox 74 Diesel conversion bur didn't change the clunk line. The glow fuel hardened it up and it was sticking straight out in the center of the tank like a donkey dick. When the tank was half empty the Saito 80 went lean and kicked the Harry Higley Heavy Hub and the prop off. It then went tail heavy and sailed through the dead snag of a pine tree backwards with no sign of wings or tail feathers on it when it came out the other side. The engine and radio equipment survived. At 15.5 to 1 I don't think I'll increase that old 80's compression.

Hobbsy

My Feedback: (102)

It's not vibes but torsional impulses, the result of a light engine and strong power pulses, exacerbated by a rich LS needle. A weighty prop helps.

Jesse Open

Hobbsy

My Feedback: (102)

I repeat, no correction required. Torsional oscillations may be a better term.

Jesse Open

I repeat,
Imbalance and torsional impulses, both are forces that contribute to "vibration". Certainly BOTH are at play, not torsional impulses alone. Flywheels help to even or balance out torsional impulses.

(Under 10,000 words, as always)

Improved-torsional-measurements.pdf

Hobbsy

My Feedback: (102)

Vibrations tend to be in line with the out of balance condition torsional impulses would revolve around the crank center line.

Jesse Open

Sorry, your personal definition doesn't change the real definition.

https://fluidampr.com/what-is-torsional-vibration/

Hobbsy

My Feedback: (102)

That is just a whole lot of words saying what I said in a few.

Jesse Open

You should have said it with fewer words and saved the need for correction.
Sorry again but NOT. You said it is NOT vibration, it is.
I said it is vibration. Part from natural imbalance, part from torsional impulses.

It IS vibration, your first statement was in need of clarification, like it or not.

https://en.wikipedia.org/wiki/Torsional_vibration

http://www.arpnjournals.com/jeas/research_papers/rp_2015/jeas_0915_2472.pdf

Captcrunch44

Jesse Open

"Oscillation"?

Okay:

1. Oscillation

   

   Oscillation is the repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. The term 'vibration' is precisely used to describe mechanical oscillation but used as a synonym of 'oscillation' too. .......

Sorry Cap, it is a vibration. Plenty of support provided from engineering sources.
Had he left out the "not vibes", it would have been 'correct". It is indeed vibration, as I originally said, regardless the source.

Glowgeek was quite accurate referring to "vibration", as I also replied, the vibration is made up from several, not a single force.
"Torsional vibrations"
86-torsional_vibration_guidelines_-_tdf&clh.pdf

https://community.plm.automation.sie...it/ta-p/354698

Hobbsy

My Feedback: (102)

Glober, I was all set to run the 50 with a few different props but got roped into installing brakes on the front of my son's 94 Explorer. It's a 4x4 so it ain't gonna be fun. I'll get to it though I promise and type a whole lot of wrong stuff.

Jesse Open

It could happen....again

Glowgeek

Yeah, I get that a lot. My kids (adults now) deliberately forgot everything I showed them growing up so now they can claim ignorance and have me fix all their crap.

No hurry on your test runs Dave. Thanks.

the Wasp

My Feedback: (1)

hey, I wont go into details, but I sure got suckered good again over on a other RC forum, I did a trade over there, the classified add said "brand new", haa I took it to be true, sent stuff I should get $100 for, in fact I was a nice guy, thinking it it was brand new and never used, I asked if he could use a couple things and when he said yes I sent 2 things I could have sold for $20, hey,> I'm a nice guy LOL,, well the thing came and I could see surely it was used a lot, I tested it and it does not work correctly so it is 100% useless.. so I PM'ed the site yesterday, I told them about the classified add and how it said it was brand new, and asked them how I should go about this with the Seller before I make a official complaint with the site, but no reply back to me yet form the site,

edit, think about it tho, if I end up sending it back I will be out a total of $30 for shipping both boxes, so ether way I'm suckered !!

the other thing I got suckered on (over there) was a muffler, LOL here too the muffler looked clean, actually it looked great, so when I sent the money order I put in a extra $4 to help pay the shipping, LOL when I got the muffler it was totally F n useless, the flange was cut so short the muffler would hit on the engine mount, it was one of those wide Bisson Pitts muffler, it would have taken $35-$45 in welding to fix it.. when I pm the guy he blamed me for not knowing how to fix it LOL, and at one point he said "all the older guys" he fly's with says there is nothing wrong with that muffler, at that I knew I was dealing with a punk kid, he did say he would send me back $10 but it never came..

any way, never again, never again will I deal over there unless the seller has 40 or more good trades

rant over LOL

2nd edit, Saitos are good, Saitos are great, I had one on the table when I ate

Jim

Captcrunch44

Glowgeek

My wife must be a Saint. I assembled my Sbach on the dining room table, with her blessing of course.

Hobbsy

My Feedback: (102)

Glober, If I sense that the engine is still limbering up some, I'll run that right out of it.