RE: SuperTigre 4500 conversion
 

This is visable at night running with no muffler on glow you have flames coming out the exhaust port (almost a blow torch) hence the muffler very hot and a waste of fuel
on diesel, none its all over when the port uncovered at the bottom of the stroke all fuel consumed as Recycled flyer pointed out this explains the lower fuel usage too- along with more BTUs per unit of fuel burned (need less) martin

RE: SuperTigre 4500 conversion
 

Greg asked me to take a look at this thread and comment, so here goes:
The MA classic has a prop load factor of about 1.25 - 1.3 (I have too few data on this type to be precise)
@6660 rpm, a 20x10 prop produces about 3.3hp during a static run, and about 20 lbs thrust using fish scales. At these low rpm it seems right on the money to me for the large tigre, battered and worn. With a smaller prop the power will be higher.
A 20x8 @ 7000 will produce about 3.1hp.
You may need to download the latest, though I doubt I ever got 6.6hp with your data even in the very earliest versions of my calculator.
www.mvvs.nl/MVVS/main_bestanden/MVVS%20-%20propellerlist.htm
An update will soon follow to reflect the effect of diameter pitch ratio on static thrust better, as published in NACA report 447. Using these data, the three blade prop gains fields of use.

RE: SuperTigre 4500 conversion
 

Pe', on the chart I saw of your's you used a factor of 1.4 and the final HP was 7.02,just like I stated. that must have been something else I''m going to have to start thinking about Diesels having FP like fourstrokes instead of paper HP.

RE: SuperTigre 4500 conversion
 

Dave, you're right about that. The trouble is to make an informed selection of prop, we need a torque curve for the engine. Most engines would do better to run larger diameter props. The only time peak HP really seems to matter is when all out speed is required. ANd quite honestly most sport models would gain more speed by streamlining, rather than small move up the HP curve.

I put a Super Nylon 12x7 on my FS-48 diesel this summer and it far outperformed the Super Nylon 12x6(closer to 5.5" pitch), even though it loaded up the engine a bit. Flying season is just about over here, but I might see what I have in 11" and 12" Super Nylon three blade props.

RE: SuperTigre 4500 conversion
 

Hobbsy,
can you post the data you used for input in that chart? I then can determine where you went wrong and explain. A 20x10 prop with 1.4 factor needs to run at 8350 rpm to get 7hp. At that rpm, the prop will bark. (My calculator has been wind tunnel tested by students of the CA university, and found to be 0% up to 5% pessimistic)
About paper tigers: As soon as power figures are published, they become paper data. Some are derived from actual measurements, some are just marketing tools. Whichever way, they need to be read with caution, because real world power is defined by prop diameter and pitch, together with recorded rpm. If the engine cannot reach the rpm of the published peak hp, real world power will be less.
Example:
I tested an engine at 11.5hp peak power. One final user just barely got 7hp, due to wrong prop and muffler choice. Coaching him to using other props and mufflers, he even exceeded my measurements.

RE: SuperTigre 4500 conversion
 

Pe', I got that from one of your charts where you have about four different scenarios, different diameter, pitches and rpm.

I ran my unbroken in ST 2300 today using a Mejzlik 18x10, it shows promise at 6,900. I may convert it back to glow for another hour, the flipping comprsssion is a little soft.

RE: SuperTigre 4500 conversion
 

Hey I got a couple of 4500's siting around. I might try and Dieselize them since glow would be like $5 a flight.

How much is Davis charging for the 4500 head?


On Hungarian Mo's prop calc I get

18.9 static
3.19 HP
62.9 mph
with a 20x10 at 6,650

RE: SuperTigre 4500 conversion
 

Amish warlord They go for 149.95 on his site, but that combo should last a lifetime , still cheaper than buying a gasser alsp martin
you already have the engine

RE: SuperTigre 4500 conversion
 

Ya but, I hate to spoil it, the cost of model diesel fuel is much higher than the cost of glow fuel. Gas engines are expensive up front, but save a lot of money in the long run if you use the engine a lot. I would convert my engines to diesel if I could buy cheap diesel fuel. My first model engine ever was a diesel back in 1974, I love 'em.

RE: SuperTigre 4500 conversion
 

Using only 50% as much fuel is a big plus, to me, RC flying, owning a Martin Guitar and having a Harley are all impractical things, so worrying about a few bucks for fuel doesn't make much sense. I fly Diesel for the fun factor and the fact that flying one draws a crowd. A couple of years ago I was in Burches Garden in south west Va. and started up my Super Tigre .51 which was on a USAircore KnightHawk. Every person there stopped what they were doing and watched me fly.

RE: SuperTigre 4500 conversion
 

Hobbsy think it is practical , no extra battery for ignition, no RF shielding required either on 72 or 2.4 freq, and 2.4 can have issues too martin
still the KISS principal Not going thru the other pluses again we already know them and outweigh precieved negatives
and a day out on the field still less than the golf course as one example, horses? like em, boarding and feeding big bucks

RE: SuperTigre 4500 conversion
 

Ok, you guys talked me into it. But I don't know which engine to convert:
Super Tigre G51 (Chinese with new piston ring)
Fox 74 Eagle IV (with new carb, piston ring, and bearings)
Norvel AX-40.

I know Davis Diesel has conversions for the Super Tigre and Fox, but not the Norvel. NV Engines has indicated that they might come up with one for the AX-40.

I could put the ST51 in my Sig Rascal 40 or the Fox 74 in my new Phoenix Extra 330S.

I also need to learn how to use Pe's power calculator spreadsheet. I looked at it and didn't know where to start.

RE: SuperTigre 4500 conversion
 

Go the ST 51 great engine, and not going for your lungs on $$ a great start into diesel, have the ST 40 and ) issues, none, Norvel not slamming them but the STs with davis heads a 12 on a scale of 1 to 10 martin

RE: SuperTigre 4500 conversion
 

H, if you happen to already have a Fox .46 ABC it's a good conversion too, just not quite as strong and the .50. The ST .51 is very user friendly an will turn a 12x6 three blade at just about 10,400.

RE: SuperTigre 4500 conversion
 

Martin, I meant that hobbies in general are not very practical, all of us could live quite well without them, but who would want to I still have my first glow engine a McCoy .36 I got for Christmas in 1956.[8D]

RE: SuperTigre 4500 conversion
 

I just happen to have a 12x6x3 blade that I purchased for the Fox 74 to put on the Extra 330S.
Is there a smaller muffler I could use with the diesel ST51? I have the stock muffler and a MACs one-piece. But I would like to have a small manifold with a long flex tubing because I would be installing it inverted in a Rascal 40. The Rascal 40 has a wood engine cowl and I would like to fit the manifold inside the narrow cowl. Similar to a PAW manifold if possible. Is that asking too much or is that achievable with a converted diesel?

RE: SuperTigre 4500 conversion
 

Top Flight has a pretty neat little in cowl canister muffler and header that might work for you.
http://www3.towerhobbies.com/cgi-bin...XHY74&P=ML
and
http://www3.towerhobbies.com/cgi-bin...XHY77&P=ML

I could se one fabricating a header like this and then using a tube to connect up a external muffler as needed.
Fox used to make a "after muffler" which was a sheet metal rectangular box silver soldered with a inlet and a outlet. But they haven't made it for many years now. But it shows up every now and then on Ebay etc.
How about that they happen to have one here http://www.ebay.com/itm/FOX-After-Mu...item519b98e0e0

Tatone used to make a exhaust header for engines, that you could attach a tube to one of three outlets for cowled engines too. A diesel isn't affected much by a small muffler volume, so it would work good on a diesel.
Like this one http://www.ebay.com/itm/TATONE-3-TUB...item2ea5b7e400

or maybe http://www.ebay.com/itm/TATONE-QM-1S...item2ea3d4a47a
They make a end outlet and a side outlet version of this one
maybe this one http://www.ebay.com/itm/TATONE-MOUNT...item2c58e959da

RE: SuperTigre 4500 conversion
 

WOW! that is a bunch of calculators I started out with. It was floating around on the 'net. So obsolete now that I even don't have a copy. That set of calculations triggered me into designing a better one.
Please download the latest from my web page. (propeller selection button sheet)

RE: SuperTigre 4500 conversion
 

Thanks for all those links earlwb, I will be doing a lot of homework now!

RE: SuperTigre 4500 conversion
 

Thanks Pe', I'll do that very thing.

H, this is what I consider the best of the available In Cowl mufflers. They have a neat sound in addition to being very light.

http://www.bissonmufflers.com/en/muf...ting_id=114065

RE: SuperTigre 4500 conversion
 

I have one of those for another engine. It does sound nice. The problem is that the plane I hope to use it inverted and the cowl is narrow.

RE: SuperTigre 4500 conversion
 

I have a bisson on both my OS 160 FX and my Supertigre 2300 and most people think that I am running a gas engine.

RE: SuperTigre 4500 conversion
 

On a Diesel engine the Bissons have a nice purr rather than the harsh bark of a gas engine.

RE: SuperTigre 4500 conversion
 

I am curious about TX  you will choose for your hobby;)

RE: SuperTigre 4500 conversion
 

[b]For anybody that's interested we have a new in the box ST 4500 and a slightly used one