My question: What is the difference in crankcase wideth between a Thunder Tiger .46 and an Irvine .53? I have the TT46 and am thinking of getting the .53 maybe later. Will I have to do significant surgery to the Sledge to get it to fit later?

I know this is an engine related question, but the Irvine is used by many Funfliers so more knowlegable people might see my query here.
Thanks

I know that a OS 46 SF and an Irvine .53 will fit in the same spot.... I believe a TT 46 has the same exact mount.... So I believe it will require no changes.....

I know the bearings for the TT 46 and OS SF are exactly the same... Just stold a set of bearings out of a TT 46 for my OS SF... Worked like a charm!

After seeing Jeff Williams fly his Sledge... I might try a MVVS .49.... The motor is a little finicky... but it sure has awesome performance.

GarySS, the motor mount spacing it 1 7/16" which is the needed spacing for the MVVS 49. It will also fit many other engines, I have a guy wiht a Irvine 53 on his and I think it was minimal sanding for a good fit. Jeff Williams

Hey Jeff, what rpm's where you getting with the mvvs 49?? It seem to be turning up good.

Propnut, the MVVS 49 I had at memphis was a new one, maybe 10 tanks thru it. I changed to a different glow plug today and got much improved idle/transition. I love that engine, my other 49 runs even better but it is well broke in. I have not tached the newer one but my other runs about 14.5K on a zinger 11 X 4 which is the only prop I run on my profiles with that engine. Top end is not what I like about it, the transition is really good. Do you recall my engine died on my last limbo attempt? Well today I went to change glow plugs and I found out why it died, the glow plug was almost completely unscrewed. Bummer too because I had enough time to make that last limbo attempt, oh well at least 50K was not on the line. Jeff Williams

What glow plug do you run Jeff?

I know a YS63 will fit right in there..

I'm a loyal Irvine 53 guy, with the UT muffler it turns the 12.25 X 3.75 about the same as Jeff's getting with the 11X4, and weighs (with the UT) about what the 63 weighs.

So I figure what the heck, I'll try a f-f-f-four stroke.

7 replies and nobody has said Saito .72 or YS .63.........

Sad.


(My Sledge is awesome with a Saito .72)

OOOPS......

Didnt see your reply Chuck.

Hey Paul,

The Suki looks great!

Thanks Wayne....

I can't wait to see you fly your stuff with the 4 strokes.... I just can't see what you see in those motors....

Make a believer out of me!!!

Thanks for all of the input........I'm still deciding. Already have a TT.46 12,300 RPM with a 11.5x4 on a 4.5 pound Extra Special, 10% fuel at 1,800 ft altitude. I would say performance is OK so I may just go with the TT at first and then maybe switch.

I just got the kit last week, I plan on building it this weekend. I am going to be using an Irvine 53 simply from what I read about them here on RCU. Hope to have it covered and ready to fly by the end of the month.

Thanks
Mike Badger
www.Aero3D.net

That would only take about half a tank of fuel. Then you'd be calling Horizon for a Saito. I promise.

I've flown a couple of airplanes with the Saito 72, and I was not even close to being impressed, though I am comparing it to the Webra 50! LOL
In all honesty, I haven't seen any reason to change to a 4C, though I owned them and tried them.
My 2 cents.
Kevin

Kevin,

Funny. I switched out my Webra .50 for the Saito .72 on a Top Cap.

Everyone has their own preference...

I really want to see you fly Kevin... But I doubt if I'll be call Horizon for a Saito... Had one.... Wasn't impressed... I just want to see what YOU can do with it.....

What I can do with what? LOL
Kevin

Well, on Saturday I was using a Rossi #9 glow plug but yesterday I switched to an OS 8 and thought the low end and Idle was better. Jeff Williams

Hey paul, you just didnt give your 72 enough time to break in and get the needles set properly. It has great power in my hard bet at over 5 pounds. Jeff williams flew my bet and he liked it and had it tail touching corn stalks.
I really like the irvine 53 on my sledge there is so much extra power but the saito 72 is also an excellent choice. I would not want to put the extra weight of the ys 63 on it myself although I do imagine that pump would allow for better transition. I do run 25% nitro in the 72 when I want top preformance
Irvine 53 - quicker spool up, helps pop the tail over in a waterfall
saito 72 pure thrust a little slower transition, easier to set it and forget it
It's all good

The weights of these three engines (72, 63, & 53) are actually pretty close.

The Saito is the lightest at 16.6 oz w/muffler. (Horizons #)

The YS 63 is a little more than an ounce heavier at 17.9 oz w/muffler. (The weight on the pspec site doesn't say with or without muffler, so I weighed it w/muffler, and the 17.9 is w/muffler.).

And the Irvine weighs 13.91 oz (Just Engines #), but this is without muffler. I don't think smallfly uses the UT muffler, but if I put the Irvine on it would have one, and it weighs 4 oz. So the Irvine 53/UT combo that I love weighs the same as the YS 63.
Sig gives the weight w/muffler at 18.2 oz, so it is actually heavier than a YS 63 with stock muffler.

So the engine I chose weighs 1.3 oz more than the lightest of the three, right out on the front. I countered some of this with CF LG. And I build light as possible (I replaced a little of the wood, but not much, and didn't do anything else to radically lighten it, it's built pretty much per plans).

I think you will get as much as an ounce difference between an APC and wood prop, so this ounce doesn't concern me much.

I don't think it's gonna be a pig, I guess we'll see.

Had the opportunity to see Wayne fly his Saito .72 powered Sledge at the 1st Annual I'net Flying, this summer. Nothing to say but phenominal! A great plane, with a great engine, with great hands behind it.

Suffice it to say, the Saito had great response, PLENTY of power, and flew the Sledge with authority.

Of course, Wayne is no slouch on the sticks, so much so, that I had him first-flight my Seduction - I am STILL trying to do a few of the moves he put it through...thanks again, Wayne!!

I am now looking for a .72 to put on the Seduction, to compare with the .70 I have for it...

R