Jesse Open

Had a 14-6 here. It pulled right at 9250 today using the Chinese and the Fromeco
Not sure where the APC 13-8 differs much from the 13-6 aside from pitch, and the 13-6 spun up to 10,000 RPM on the same .82.



At least eight years worth of castor \"epoxy" on my most used .82. Still slick and smooth.

Glowgeek

Right, an APC 14x6 puts significantly more load on the engine than the 13x8. Really surprised me with that 13x8 Scimitar design making the 82 seem like a real powerhouse.

APC 13x8 @ 10050 calculates to 1.670 hp
APC 14x6 @ 9250 calculates to 1.313 hp
My HC 82 with your custom muffler will turn that same 14x6 at 9650-9700 which calculates to 1.5 hp. Pulls my 6.6 lb. Sbach 342 out of a hover with excellent authority!

FWIW, the 82 is rated for 1.4 or 1.5 hp depending on who is selling it and HH removed their benchmark rpm and rated hp from their ad. Wonder why. In the end they're just numbers but interesting to me nonetheless.

The internals of your exopied engine look wonderful.

Jesse Open

Not "seemed" ....powerful.
The 82 Saito, not only mine, are rather powerful, You gave numbers for a 13-7 and I replied I never ran an 82 that lightly loaded. We were comparing stock FA-72 on a 13-6 to stock FA-82 on a 13-8 prop of similar design. Try that 13-8 on a 72 some time.
The 72 will not turn a 13-8 anything near what the 82 will. Be assured, that muffler also increased the RPM on my stock 82

The difference of course is where that power occurs in the rev range.

Glowgeek

I've never posted numbers on an 82 with a 13x7, not enough prop. If I posted that it would have been a typo. I'll run the 72 with a 13x8 tomorrow and report back. May even try a 14x6 for fun.

Yes, they have to be propped within the correct rpm band to show good hp numbers. When done so most Saitos make at least 0.103 X CC in horsepower on 15% nitro.

Jesse Open

The 82 with APC 13-8 combo has worked very well on most of my planes, Planes like the Flybaby, Funky Cub,Astro Hog etc. Good vertical, realistic (not the herky jerky, schiztoid, spastic stuff) and excellent flat out speed. Works out very well on the 82. The 72, not so hot.I only mentioned the 13-7 because you had quoted the 13-7 in your 72 numbers.

In those applications where I am concerned about horsepower, the Saitos remain on the shelf.

Glowgeek

FA72
APC props
15% nitro
Temp 64°f
Humidity low
HP is calculated

13x7 @ 9930 (1.409 hp)
13x8 @ 9550 (1.433 hp) Equates to .121 hp/cc
14×6 @ 8850 (1.15 hp)
14×8 @ 7950 (1.112 hp)


FA82 (Gary's)
13x8 @ 10105 (1.697 hp) Equates to .123 hp/cc
14x6 @ 9250 ( 1.313 hp) Equates to .095 hp/cc

I think I may switch to Zoar props for testing due to the wide disparity between the two different style APC's props ie Scimitar blade design vs standard.

Hobbsy

My Feedback: (102)

Saito 65 with "N" on the right lug, new bearings and gaskets.
Fuel======Wildcat 10% with 18% full syn.
Prop Xoar =====13 x 6
Plug======Taipan 4 c
Exhaust===Stock cast not revised
Temp=====72
Max rpm, sightly unsteady 10,080
Max rpm rock steady==== 10,050
Idle, very nice smooth==== 2,000

Confession after some comments.

Glowgeek

1.252 hp from a 65 on 10%? Better fess up to that high compression domed piston, late model 2 needle carb and drilled out muffler baffle.

Looks like the 65 you sent me is at the post office. Woohooo! Too bad they won't drive up the rough and rutted lane to my house or I'd have it already.

Jesse Open

For my airplanes and flying style, that APC is a great match for the 82. The 72 is not happy trying to pull the 13-8 and the planes are noticeably slower and far less responsive on the 13-6.

I will run the 14-6 again as that last test was a quicky and I didn't bring the good tach along. I have a xoar 13-8 and possibly a xoar 13-6 to try.

If I run the new Motul oiled fuel at 12% oil with 10% nitro may be possible to pick up a couple hundred rpm as well.

I rarely go to these extremes, rarely even get the tach out. I bolt a prop on and fly. Observe the vertical, check the GPS speed etc and fly the prop I like best. With the 82, more often than not APC 13-8 is the go to .

Hobbsy

My Feedback: (102)

Well sir, it's not a high compression 65, but I very carefully adapted an 80 carb and intake pipe to it. I didn't think it would make a difference. At first the compression was a little soft, but it came around after about 15 minutes at various speeds from 5,000 to 6,500, then I went for it. It actually touched 11,000 far a few seconds with the aid of a breeze. of course those don't count. One snake in the oil is that when the tank was half empty I had to enrich it a few clicks and than again when the 14 oz tank reached near empty. For full throttle only. I drilled the intake port to 8.5 mm and the 80 intake pipe slides in like silk. I tried to use an 82 carb but the intake pipe is too fat and the 82 pipe too short. It was fun. With a Cline regulator it would be a good mod.

PS, I hope you love that 65.

Glowgeek

Did it not run lean in the midrange with the 80 carb? Are you running an 80 muffler as well?

Hobbsy

My Feedback: (102)

No sir, I cut the throttle and saved it, then went full throttle and again it went lean and kicked the prop off. I back off a quarter turn and re started, leaned it to peak again abut 4 clicks rich of the previous setting. Cutting to midrange would save it every time as I experimented. It leaned again at near empty but not yet sucking bubbles.

PS, Gary the exhaust threads on the HP 25 are 8m x .75.

Jesse Open

Good story on the 65, almost predictable on the fuel draw issues.

I was thinking on the HP to Saito muffler you may just drill and tap the inlet to M8 x .75.

Minimizes the total number of size transitions.

the Wasp

My Feedback: (1)

I was going to ask if you thinned the blades down to nothing with an E-sander LOL

Jim

Hobbsy

My Feedback: (102)

Thanks Jim, no don't mess with props, the prop drive messed with it though, it was 90 from where I first mounted it, the serrations on the prop driver plowed a groove in the back of the prop.
I stated that the muffler is the non revised version, as you can see I revised it on the lathe. I'll run it on the S&W 15% today.

Glowgeek

Well Dave, you'll have to let us know how that 65 handles with that 80 carb and 15% nitro. Watch your engine temps and smoke production throughout the midrange rpm.

Hobbsy

My Feedback: (102)

I certainly will do that hopefully today.

I cut the threads on a Saito 30 elbow down to 8m x .75, the Saito muffler looks like it belongs.

Jesse Open

Looking good.

Jesse Open

Just finished a three engine run-off .A well abused FA-82 ,a near new FA-72 and a medium run FA-65. Got a good reminder of just how nice that FA-65 can be!
All using the 14/14 fuel, castor-sinthetic blended oil:
FA-82 MA 13-8 9200
Rev-Up 13-6 11,100
Xoar 13-8 9600
Xoar 14-7 8800
APC 15-7 8700
MA S-2 14-:7 8850
APC 13-6 10,800
APC 13-8 10,000


FA-72 APC 12.5-6 10,900
APC 13-6 10,200
MA 13-8 8600

FA-65 APC 12.5-6 10,850
"" 13-6 10,300
" 13-8 9700
" 14-6 9200


Post Script:


On the 14 and 15 inch plastic props, the FA-82 would settle down to a very nice 1600 rpm tick-over. I made a video, will convert to you-tube and post later on .

FlyerInOKC

My Feedback: (6)

An interesting set of numbers!

Glowgeek

FA65 High Compression

15% nitro
APC 13x6
Temp 70°f
Humidity low

Peak holding at 10500 rpm
Idle steady at 1990 rpm

Wicked little engine! I think I'm in love.... Thanks Dave!

Glowgeek

That right there is why I'll be switching to Xoar props for bench testing. The blade profile doesn't change radically as it does with APC props.

The APC 13x8 @ 10000 calculates to 1.645 hp. No way the 82 makes that kind of power.
The Xoar 13x8 @ 9600 calculates to 1.455 hp. More in line for an 82 running on 14% nitro/14% oil.

Hobbsy

My Feedback: (102)

You can't just arbitrarily say a Saito 82 can't make a certain hp figure when in fact it did. You're going at this thing subjectively rather than objectively, in other words you're looking for things that agree with your thinking. You need to let the facts tell you what to think.

Jesse Open

And that right there is why I rarely if ever rely solely on prop rpm on a test stand as anything more than a minor starting point...... As I said earlier.

The proof is in the flying. Simply put, there is no other prop that the 82 will turn at 10K that flies my planes anywhere near as well as the APC 13-8. Period!
The combination of vertical distance and flat out speed is perfect on the planes that I choose to power with the .83. Neither the Xoar 13-6 nor Xoar 13-8 approached the APC. Likewise the boggy Master Airscrewed props.
I fly planes, not tachs, numbers and test stands.


Note the Saito FA-65 turned virtually identical RPM on the APC 12.5 - -6 as the vaulted FA-72
The Saito FA-72 is strained badly on the APC 13-8, the FA-82 loves it.

These numbers were all on th same day, same fuel, same props. Engines adjusted carefully and rpm stabilized. I had no dog in the hunt.

Captcrunch44

yup did that same thing 80 carb and intake on my 65.
I have it on a 3ch senior what a hoot to fly.