Glowgeek

Yeah, good question. I think Horizon Hobbies benchmarks the engine, no other retailers list a benchmark. HH shows the benchmark prop as a 14x5. On the apcprop website it shows the shaft hole to be 5/16" and only available as an "N" (narrow blade). The apc 14x6 has the same 5/16" hole.

EDIT: Looks like the saito 120r3 manual states benchmark apc 13x6 @ 9400.

Glowgeek

Looks like plenty of power and plenty of fun. I'm guessing he's running a 13x8 prop.

Jesse Open

So, they must have been quite trouble free as long as you kept them away from inept hands

Jesse Open

If not, Dave can probably make one.

Wait a minute... APC uses a supplied bushing in the counterbored rear of the prop hub IIRC.

Glowgeek

True, back when they supplied them.

Hyjinx

I ditch the obgs and light the glow plugs with a external battery. These motors run and idle just fine without on board weight and gizmos for me.
Completely unnecessary for my group if radial engines.
from 3 cylinder Saitos to seven cylinder Seidel's.
I run no obd on any of them.
More power and no gas Gizmo ballast.
simply glo and go.
A few of my flying friends add ignitions and spark plugs to glo radials for some reason. Guess they just have a lot of cash for jinping😁
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Jesse Open

Very well said.
Those who can't tune, spark it.

FlyerInOKC

My Feedback: (6)

I remember seeing an open rocker OS .60 4 cycle idling on spark ignition blowing little smoke rings when I was a kid. I thought it was a the coolest thing I ever saw. Now that I am the one running 4 cycle engines I have no desire to convert them to gasoline and I have no desire to add complexity to an already well designed and fine running engine. I don't see any advantage to spark ignition for the additional weight would add to the aircraft. Granted I prefer to stay at a scale having a 84" to 92" wingspan with the odd design at 96" but no larger. Granted if I was building larger airplanes like 1/3rd scale or larger I might feel differently but I know what fits my individual needs.

Hyjinx

Lol Gary
Can I have permission to use that zinger on my gizmo infatuated "afraid it will quit on me " buddies.
Love this stuff!

acdii

Only reason for OBG thinking is ease of starting and less things protruding from the fuse, would rather have two small switches then a switch and a plug port for the igniter and then have to haul around the power panel and cords. Nothing fancy either, just a rocker switch used as a kill switch for gas engines that I have laying around I never used.

On another note, what size is the bold for the cylinder to case for the FA-72? Seems I didn't get one tight enough and lost it in flight today. The engine was always such a good runner until I had to replace the cylinder after a crash. I got it idling nice today, no change in RPM on or off glow power, smooth transition, but about 5 minutes into flight I was flying it slow just off idle and when I throttled up, it burbled and died. It wasn't my best landing either due to the crazy shifting winds, and nosed it into a just cut hay field, bent the right leg a little and dented the LE. Up until then it was running superb was flying at half throttle mostly too. I noticed that when inverted it sounded a bit off too. I set the needles with a half tank, pointed the nose straight up at WOT, no issues, etc, and I think only used about a 1/4 tank if that before ti quit.

I've about given up on this plane it has been nothing but trouble from day one. My last one never nosed over while taxiing, but this one does, and the CG is identical. It is squirrely at times in the air as well, will fly straight, maintain level flight on one pass, turn around and have it go all over the place. I double checked everything on the plane, everything is nice and tight, but the engine quitting again pissed me off and I just stuck the plane in the back of the trailer and packed up.

Was going to maiden the Chipmunk util I discovered I forgot to open the cowl enough to put the glow stick on. Can't start the engine without it. Maybe just as well, the wind was not cooperative today, forecast showed 10MPH gust and a 6 MPH breeze. BS that was no 10mph gusts, more like 15-18 and south and south east was the direction, it was constantly changing. I probably would have had a better day had I not had to work until 3 in the morning today and didn't get to bed until 3:34 AM. Tried to sleep but kept waking up, finally got up around 11, and felt miserable and grumpy all day, the antics of the SSE didn't help either. I did get the 120R3 mounted to the test stand though, so there is that.

As far as the pro goes, under E. Preparation for Engine starting in the manual, step 4 For test prepare APC 14x6 prop. So if anyone was wondering why I asked my question above, I am going by what the manual says. I guess it is time for me to find some bits and pieces of stock for my lathe and mill and start making some parts. I will also dig through all my parts containers and see if I can find some of those bushings mentioned above. I recall having some, somewhere.


Oh one more thing, my power panel is dying too. The GP rheostat must be worn as I can't get proper adjustment to the plug. So add that to my list.

Jesse Open

I think that I still owe you some silver solder. PM your address again and I will send it. I will also toss a few cylinder base screws for that Saito.


Oh, what size is that potentiometer in your power panel? Usually a 10k or 5k ohm. I probably have that too. Let me know.

the Wasp

My Feedback: (1)

I wanted that 100iT so bad that was on RCG yesterday. but the seller had a seller rating of 0, and $700 was a lot of MooLaa

Jim

Jesse Open

There was a 200 inline on eBay last week for near that price.

Monty Python

I've since had a quick look at the history of al menasco and see that his engines powered ryan st and gee bee aircraft. The article said that his racing engines were a bit temperamental with cooling issues etc but that the production engines were very reliable, whereas the typical production dehavilland inverted inline four or six engine in any of their tiger moth and similar type required a lot of sympathetic coddling along so you remained airborne. Their racing engines in aircraft like the mew gull and the dh comet twin were much better.

Lonnie do you think an apc 13x8 is a bit light for the fa120r3? any one of my fa82's on light nitro will spin an apc 14x6@8900 in flying tune.

Glowgeek

Pete, Ive never run a 120R3 so it's hard to say. There's not a terrific amount of prop/rpm reporting online. The benchmark numbers indicate it makes power somewhere between an fa72 and fa82 but in that video I posted the 60 size Corsair is really flying great. Acdii will have to let us know.

Hobbsy

My Feedback: (102)

There is an excellent Saito 80 GK for sale in the Market Place, never run and in a Black and Gold box, all papers and tools included. $200.00 shipped. Not a bad deal.

acdii

According to the manual, the 120R3 will spin a 14 x 6 APC @ 9500 RPM. It seems odd though because 10,000 is the max in the air, and the ground range is 8500-9500 and another part, under fuel flow has the APC 13 x 6 @ 9400 RPM on 15% Nitro. Static thrust is 3.5kgf with the 14 x 6.

It gets even more confusing, prop sizes are 13 x 8 -14 x 6. So where did the 13 x 6 come from. This was from a manual I downloaded specifically for the 120R3. The manual that came with the engine has labels applied for the 120R3 since originally the manual did not have it listed. I guess wont know what it will do until I get it hooked up and running. I should probably break out a new bottle of go juice for the break in too, I only have about an inch of fuel left in my current bottle that has 3 seasons on it, and probably is no longer 15% nitro by now. I have a full unopened case of SIG 15% 4 stroke on a shelf in front of me, so have plenty of fuel, and also have an unopened bottle in the trailer too.

acdii

I know I have some of those somewhere, just have to find them. I will get the starter box out of the trailer and pop off the panel and see what it has. I bought it used 9 years ago, so no clue how old it is. I'll PM once I find out.

acdii

Geez this thread is dead today. Watched a few 120R3 videos and found one guy was running a 16 x 8 MAS on his turning 7400 RPM. I will see how mine does with 14 x 6, and then swap out to a 14 x 7 x 3 and see what it does. Have it all set up on the PSP, just have to take it up stairs and set up the workmate and fire it up. Probably tomorrow.






Only spinner I have on hand that will work is that big ugly yeller one. Once I get it mounted on the Corsair I will have a more appropriate spinner, but for now, this will work for using the starter on it.

Glowgeek

If you're talking about the "crazyengines" channel it did appear to reach 7400 rpm momentarily. If your Corsair would allow that 16x8 prop to unload to 8400 rpm in the air you'd have a 55mph hi speed pass.

Beautiful engine btw

Hobbsy

My Feedback: (102)

Mike, the rear facing vents will be in the mail in about a half hour, I made one new one a stole one from my 82-b. The others seem to have evaporated. CRS is worse than I thought, Take care, Dave. I made a second trip to my Daughters for a memorial in her back yard, it was brief and very nice. It was by invite only so her sons dope head friends would not show up. She bought my Saito 150 for me in about 1992 for Christmas, they were $449.00 back then.

Jesse Open

Please check out this magazine. I have been buying it since 1984. Loads of information.

https://www.homeshopmachinist.net/


There is a free sample offer on the website.

Hobbsy

My Feedback: (102)

I did, I'll take a closer look a little later, Thanks

FlyerInOKC

My Feedback: (6)

I received an email from the USPS with an estimated delivery of Saturday. Who knows they may even be right.

Hobbsy

My Feedback: (102)

That must be something new, Thanks