acdii

That is pretty much where it is at now. Good transition, I had leaned the LSN just a tad too much and it stalled on throttle up, backed it off 1/16th and good low end and top end and smooth transition. It will sit and run about 4000 all day as long as there is fuel, but it had that 2 stroke sound every so often. The HSN has a 1/2 turn range, with little change in RPM still, so I know its still not quite right. This was a used engine and have not run it but for 2 flights before it started acting up, so wondering if the carb might have some gook in it. When I compare the LSN depth to the FA-100, it appears to be about the same on the 125. That was my first clue the LSN was way off, it was flush with the arm. As it sits now it should fly fine, but I may still tinker some more with it to see if I can get the miss to go away.

Glowgeek

Acdii, is the compression and fuel consumption normal?

The reason I ask is because if the valves are leaky or the ring lands have caked on castor the engine will have less compression and use a lot more fuel than normal. If it is using a lot more fuel than normal at wot the hsn will have less sensitivity like you are experiencing.

Hold the prop at half way through the compression stroke, it should hold pressure for at least 30 seconds. If the pressure bleeds off quickly you may have a little more work to do.

acdii

Valves and rings are good, compression is really good. My starter wont spin it if I bump against TDC right away, I have to pull the prop backwards to just past TDC on exhaust for it to spin. As far as consumption, it used to suck the tank dry fast, and the oil that was on the stand was a testament to that. It was spitting out the crank vent, but now it appears normal, very little comes out the vent like it should, it is possible the previous owner belled the seats in the carb too, and that can cause tuning problems. Once I give it a good close look I will have a better idea. I got the idle all the way down to 1400 for a few seconds too nice and smooth. This one never ran castor though it, it was really clean and no gumming anywhere.

acdii

Then again, maybe this was Pete's 125 that his dog burried.

Glowgeek

Yes it can cause tuning problems but the opposite of what you are experiencing. Bell mouthing causes the needle to be overly sensitive. One click each way can cause the engine to run too rich or too lean.

acdii

Found two things, dirty HSN and bad glow plug. I flushed out the HSN side, and replaced the GP with a Saito branded one. I had a merlin in it. Miss is gone, and it runs like it should, still not getting a lot of variance in the HSN, it sits 1 3/4 turns out, but since it runs good, low idle, good transition, and WOT fuel looks to be about on par for the size of the engine, I think it is good to go now. What I found is the marlin plugs have the coil deep in the plug while the OS, Saito and Fox are even with the base. This is more than likely the reason for the occasional missing.

The other thing of note, the HSN is stiff to turn, but the threads are nice and clean, so I think the Oring may be a bit too tight. Not going to worry about it though, 8900 on the Scimitar is plenty of spinning for the Mustang. The main thing is it starts easily and idles nice with no hesitation in the throttle.

Jesse Open

GREAT!

That is fantastic news. Very happy the plane found a good home. That 65 should be perfect, the .82 was far too much .Thanks for the update.


Four hours! WOW

Glowgeek

Gary, pretty cool that your wife shares in your hobby, wish mine did. You're a lucky man.

Sometimes the Polish Princess will come down to the shop and say, "That's a pretty plane" or "Wow, when did you get that one?". Even then, there is no genuine interest, she's just trying to break my focus so she can ask me to do something for her.

acdii

Well, the P-51 is back in business. Got the 125 reinstalled, found the issue with the remote glow and corrected it, ran it in the plane and it ran very good, in fact I had to do some servo trimming so the throttle cut would work, it just sat there pop pop pop pop, 1400 RPM. SMH. That big spinner has something to do with it I'm sure. Once that was done, retracted the wheels and balanced it. It was nose heavy, had to add roughly 1 1/2 ounces to the tail It is balanced at 5 1/2". That should make a huge improvement on everything. I went and put it away in the trailer and wound up spending the rest of the afternoon rearranging planes, needed to make room for a few more. There are 13 planes in it now. Not all are ready to fly though, the P-47 needs a few new servos, and a recheck on the balance, It probably is spot on, and I could fly it, but I don't trust the servos I have in there, the elevator ones chatter occasionally. I have also had those particular servos fail over time, so not taking a chance. Going to put some hitecs in and be done with them. The T-Clips I still need to extend the needle and run the engine, I have never run it, I think it is a Saito 65. Then I have the CARF Extra 330L that is just the plane with no radio gear other than the powerbox. I just don't have room in the shop for it.

I usually store the Somethin Xtra all assembled and ready, but figured the wings are so easy to put on that I took them off so I can set the Liberty Sport on the shelf since those wings are not easy to take off. I have two 4 stars hanging on one wall, then 4 others on shelf brackets on the other wall, three big ones on the floor, and four on the shelf.

Now if only I could go to the flying field and fly! Probably wont happen until June. The guy who maintains the field is still in Florida.

Here's something I found out. The FA-100 turning a 14 x 8 turns the same RPM as the 125 with a 14 x 10. Now I don't know jack about pitch other than inch per revolution when it comes to power, but I thought that was quite interesting how strong the 100 is. I just might put that one in the Chipmunk.

Glowgeek

It takes exactly 20% more horsepower to turn a 14x10 at 8900 rpm than a14x8 at 8900 rpm.

Hobbsy

My Feedback: (102)

This was Pete's reaction to the 1.25 being the stronger engine:

Glowgeek

Sorry Pete but when I do my comparison tests I'm sure I'll find that the 125 is stronger than the 115 in some regard. Probably in spinning larger props.

Hobbsy

My Feedback: (102)

Lonnie, I believe the 1.15 and the 1.25 have the same valves, I will measure and see if they have the same carbs. Unless you already have done that, Thanks

Glowgeek

Yes, the 115 and 125 share the same piston and valves. The 115 and 100 share the same carb, the 125 has a larger venturi.

Hobbsy

My Feedback: (102)

Thanks, I just pulled both carbs, the caliper would not reach with the velocity stacks in place.

Saito 115 carb=SAI100821 code QQ UU 8.25 mm
Saito 125 carb=SAI125a821 code AG AH 8.75 mm

Glowgeek

Interesting measurements Dave. Although the 125 has a 25% larger displacement than the 100 (due only to stroke) the venturi of the 125 is only 11% larger in area. The 125 appears to me to be designed to develop peak hp at lower rpms. Testing will show.

Hyjinx

Shoot man
Only risked it twice yesterday in 13 mph winds.
Didn't fly the Saito R5
This thing is so much fun I may need to build a full scale!
That pretty little Waco is getting close to the engine mounting bench!
And whatever engine ends up on it will be round for sure.
Thanks Gary

Jesse Open

My buddy, Dave had a scratch built (his plans) 8 footer Flybaby. Has plans in a few different sizes, all are extremely fine flying planes. I can borrow his plans and get copies. Great flying machine with a 3.00 OS Gemini. You would love it. Maybe later this summer I can take you over to his place. He has some beautiful scratch built planes, but he doesn't fly any more. His Smith Miniplane powered by a Saito 3.00 twin is awesome, you would really like Dave.

Glowgeek

What's on the Waco now? I might be interested in taking it off your hands.

Hobbsy

My Feedback: (102)

Lonnie, there is a discussion going on elsewhere about the different dimensions of small fourstrokes, I did a side by side shot of the FA 40-a and the FA 30.

Hyjinx

Currently naked. Soon to be Radial powered.
Then powering over Heritage Field.
It has found it's happy place🤗

Glowgeek

Sorry, I was unclear. I'm interested in the engine that came off the Waco.

Hyjinx

Yeah Buddy
That would be a good day Gary.
we need to incorporate that into a fly day at your field too. I'll bring the Waco and you can zip it around your strip again.
Hopefully Mother Gretchen will write us a hall pass...

the Wasp

My Feedback: (1)

more flywheel effect for sure

Jim

FlyerInOKC

My Feedback: (6)

Gary, did the letter I sent you ever show up?

Mike