nextofkin

My Feedback: (8)

3.5 X 6 mm tap use a number 33 drill
nextofkin

blw

My Feedback: (3)

You are member #804

stevegauth30

Thanks moderator man. 804 it is.

mike early

I wonder what the best speed prop for a Saito 82 on 15% Wildcat would be, APC 11x11 or APC 11x12...
Anyone ever tried either?

Superspook

My Feedback: (16)

Looking for a glider launch rack or the plans to build one any info greatly appreciated Superspook in sunny Florida

FNQFLYER

Re best prop for the 82.  I use a Bolly 12x6 on the 65 for vertical drag racing.  I would think the 11 size would be under proping it.  Try a 13 or 14 x 6 or 7 APC unless you can get a "go fast prop" like SAherlock and mess around with them.  You'll need a good tacho to make the ultimate decision.
I am lucky because with careful use I have enough Bollys to last a life time.  Result of buying up every one I could lay my hands on from here to right around Australia and then trading off for the ones I really needed.

FNQFLYER

Re best prop for the 82.  I use a Bolly 12x6 on the 65 for vertical drag racing.  I would think the 11 size would be under proping it.  Try a 13 or 14 x 6 or 7 APC unless you can get a "go fast prop" like Sherlock and mess around with them.  You'll need a good tacho to make the ultimate decision.
I am lucky because with careful use I have enough Bollys to last a life time.  Result of buying up every one I could lay my hands on from here to right around Australia and then trading off for the ones I really needed.

SrTelemaster150

You can plug some values into this [link=http://personal.osi.hu/fuzesisz/strc_eng/index.htm]STATIC THRUST CALCULATOR[/link]

If you adjust the RPM to yield the HP output of the engine, you can get an idea of what those props will yield.

On my big block Saitos it comes right in on factory HP spec's.

Don't forget to factor in te APC prop.

Cougar429

My Feedback: (3)

Superspook, sent U a PM.

jw0847

I would like to join Club Saito - Thanks John

mike early

Looks like I'll be getting 110-120 miles per hour with a Saito 82 turning somewhere around 10,000 RPM static and an APC 11x12 prop on a Sundowner 36

hsukaria

It will be a tight squeeze to put a Saito 82 in a Sundowner 36. It is a tight squeeze to put a regular-sized 2-stroke 40 in it. It would be interesting to see how you manage it.

mike early

I started with a Saito 56 with a 11x9 MA prop and it was wonderful. Only compensation was to put the RX battery back in the fuselage. Then I tried a Saito 72 with a 11x11 APC prop and it required some tail weight stuck to the bottom of the horizontal stab. It was faster and better. Then I crashed the plane with my Saito 82 and I figured why not, it's the same size and even less weight than the 72 so it's in there now. I have installed an APC 11x12 prop. 11 inches is about the extent of the ground clearance this plane affords.

I've added a polished aluminum spinner since this photo with the Saito 56...

Rudolph Hart

Mike you are like a breath of fresh air to any righteous thinkin saito horsepower lover,takes a lot of thought to jam that much in there,it's the best plain out fun ever,safe too

hsukaria

For a 2-stroke, Hangar 9 was recommending a 9x6 or 7 for the Sundowner 36. So, you installed the 82 inverted like you show the 56?

SrTelemaster150

I have an FA91S W/CDI stuffed into a .40 sized US AIRCORE "Nighthawk" Turns a 15 X 5 @ 9700 RPM.

FNQFLYER

Whats with these RPM's on these bigger models.  From memory some of them are barely making factory specs.  I know some of you might think the RPM's I quote for my engines are a "bit excessive" but for those in OZ I say go to an Old Timer meet and you'll see that my figures / performance is even considered conservative.  We run "factory sapecs" foor fuel and prop size (well all most) and get factory stated performance.  As an aside I have yet to come across any of the problems (FG20 carby aside, whic was fixed by a replacement one ex factory) that others seem to have with the petrol engines that wasn't operator induced.  Read the oinstructions / book there is a wealth of info and Mike Early, I would really like to see that machine with all the new engine types one can really get performance with a cubic capacity upshift without the resultant penalties of weight that we experienced in the past.  A bit like fitting a BDA Cosworth into the old Fiat 500 trick, and probably just as scary.
  

SrTelemaster150

If you prop your engine for maximum RPM on the ground, it can over-rev once the plane gets moving in the air.

Not so much of a problem W/a JN-4 Jenny, but on a P-51, RPM can increase dramaitically in the aor when the airframe is doing 100 MPH & the prop is unloading.

FNQFLYER

Not on the P51 I restored / worked on.  Constant speed prop and the wings would fall off before you lunched the engine.  Assuming you weren't stretching the limits  eg war power (which was a number of plus 100% max RPM) or you are racing it with exotic fuels.  Most engine failures on modern engines are due to prop governor problems or just plain structural failure within the engine.Re off load in flight listen to a YS 53 or 63 at max RPM on the ground and then listen for the "upshift" in rpm at about 50feet (or less).  We counted on this in Duration to get that little bit of grunt to get out of ground effect into clean air for the climb.  (The climb was at 87.5 degrees, ideal, for 28 seconds engine run, this usually gave about 1, to 1500 feet.  And for reference the 65 Saito is not far behind on a 32 second engine run)
Note don't confuse prop rpm with actual a/c speed.  

mike early

Yes. I install all my Saitos inverted on all planes.

mike early

Too much math for me to know for sure, but some props unload more at speed than others. I am seeking maximum speed with the overpowered Sundowner 36 and the Saito 82 with the APC 11x12 prop. If nothing breaks, then I'm not pushing it hard enough. Only when something breaks does one know the limitations. No matter what happens, I can fix it....

blw

My Feedback: (3)

The Eagletree measurements I've seen (and those are only a few) bounce around 1000 to 1500 rpm increase in the air. This 'unloading' is the propeller reaching maximum efficiency due to the air being pushed through the prop disk from the airspeed of the aircraft. This is why static rpms on the ground are pretty much meaningless. When the prop starts hitting max efficiency speeds the engine has the load on it reduced, and thus can put out more rpm.

FNQFLYER

I would dispute the fact that staic thrust measurements are meaningless.  On 1 : ! a/c staic trust was always the target thrust requirement on engines runs be they piston, gas turbine, (either jet or prop) or rocket engines.
With model a/c type engines you can get the engine to "unload" to varying degrees depending on the design of the prop cuff, blade root design and the general blade design.  Best and most obvious example to us oldies in the Electra L188 / P3C.  Both had the same engine but look at the blade, horses for courses, as similar thing can be seen with the various varients of the C130 / L100 series a/c.
As for all of this, I tune with a tacho, run the engine according to the requirement of the day and have the spares to fix any broken bits.  Makes for a more enjoyable day especially when you come out on top at a competition and you take home the a/c fully assembled still. 

mike early

I usually prop all my saitos at 9000-9500 static. I've had great success with those numbers but what will happen if a Saito over-revs? valve float? piston-valve contact? Let's see the consequence.

I wish I had a Torque-HP graph on the Saito 82. But even then I would never know the unloaded RPM. Unless I had telemetry. One day I will, but I still need a Torque-HP curve. If club Saito cannot provide that, who can?

FNQFLYER

Mike, there is one of those back in the early posts, you can also get that sort of data direct from Saito  I think I also have it on my individual engine sheets that come with the engines