MTK

Just received the 33cc from Tower. I bought into the hyperbole of its supposed ability to turn larger Pattern sized props at Pattern rpm. They cite props up to 20x10, and if that proves correct in trial, I have just the ticket.....20x10 MDK hybrid

I've been playing with the SAP 30cc and have had pretty good results overall. It isn't the most ideal set-up tho since the engine is a revver requiring high rpm to work properly. I've made it work in Pattern but it isn't the better set-up (YS170 for example)

The OS on paper seems to have better stuff for Pattern. Example: OS has increased the stroke of the popular 30cc engines (SAP and DLE are the best of their type out there), from 30mm to 32.5mm, while maintaining the bore at 36mm. I have not measured exhaust duration yet but it appears to be around 155 degrees, more in line with their 140 RX and 160FX 2 strokes. Should turn in the mid 7's comfortably, I hope, with something like an 18x12, and possibly in the low 7's with a 19x11 or 20x10

I plan to use a pipe on this engine (ES40G). The header will be the Hatori return to center originally intended for the 160FX. It has required reshaping the exhaust tube a bit and redrilling the exhasut flange to fit the 33GT exhaust port. Will build a soft mount for it this weekend and see if I can fly it Sunday weather permitting..

I'll post some snaps soon

TimBle

nice one, watching with interest as I am flying a TWM Spot On Banana with a DLE 20.
The DLE is exhausting through a Weston Uk Aerobatic Mini pipe. Runs well enough but the Spot On needs a diet. The DLE seems to work best with the 16X8 oar in this application. Till my 17x6 Vess props arrive I am using these.

Planing on moving onto a larger 2x2 next year so looking around at possible engines and the Mintor 33 is looking promising. If OS claism for the GT 33 are borne out I may be swayed.

Enrique-F3A

Hello Timble,

Take care regarding Mintor Products. I own a Mintor 170 that never worked. The manufacturer (Mintor srl, Italy) is a total irresponsible company. I purchased the engine directly from them with two headers (different rise) and pipe, spent around $ 1200, including shipping and import taxes. I sent the engine back to them for repair. Accordingly to the Italian post service, they should have picked up the engine and pay some duties, they never did that and the engine was sent back to my country without repair, I had to pay all the shipping charges. They had to discontinue the 170 model due to bad quality. These people (Mintor) are used to manufacture garbage products and give no support, no warranty no responsibility, no nothing. They are liars and cheaters because they deny everything that happened.

Enrique

TimBle

Thanks for the warning. I have a local distributor who has an excellent reputation to take care of me in that regard.
That said, I have had poor experience with World Models but thats another topic.

MTK

I saw an ad for PTE 36cc... it's a gassie with rear exhaust and rear intake. The bore and stroke are more in line with what one would expect. The hp being quoted is a bit on the low side but I am wondring if this engine isn't more in line with Pattern needs? The rear exhaust and displacement are very attractive; the weight is on par with the SAP and DLE 30cc. Price is also very attractive, even if it was an experiment only to be used as a paperweight afterwards.

On my 33GT, I have the soft mount almost finished. I should be bench running it this weekend

aussiesteve

What the majority of the "lower cost" products sorely lack is a decent mid range torque curve. This is where most fall down as pattern contenders. It will be interesting to see how the OS stacks up in this regard.

MTK

Steve,

The DLE55 on pipe is very nice runner. Very smooth and extremely quiet on my soft mount turning a 20x12 3 blade. I have the weight down low enough to make it useful in a pattern application. Currently flying the 78" EF Extra with it and at around 13 pounds all up weight it is no real load for the DLE.....but terrific fun.

I might actually make weight in a pattern plane but it would be tough. Not that that really matters much at local events anyway so the engine will go in my first new prototype plane.

That's why the 33GT is so attractive and if it gave me just a bit more mid range than the SAP 180 that I've been using, it would make a compelling argument for a 10 1/2 pound airplane. However, the rear exhaust headers are much more readily available and easier to install in a pattern plane than the return to center headers of side exhaust engines, so the PTE 36 has got my attention

aussiesteve

Yes, the DLE is very much an exception to the "general low cost rule" (Hence part of the reason for my edit above to use the wording "Majority of". (The Mintors are a reasonably low price also).

I know you worked hard with the SAP 180 and repoted very clearly on its performance strengths and weaknesses. I am closely watching for your results on the OS 33 as I will be looking at a similar application some time ear;y next year.

MTK

Steve,

Speaking Mintors, what do you make of their new 38cc? It has a bore:stroke ratio of 2:1, 1.77":0.9".

Looks like they took the top end of their 55cc and matched it to a new bottom that is shorter stroked than their 33cc.

Wished they would have done the opposite and matched the top of their 33cc with the bottom of their 55cc. Would have made a 43 cc engine and with decent porting, would have given us all the power in this class engine we would want

TimBle

suggest this to MIntor. I hear they are receptive to input

MTK

Okay, here are some numbers from the first couple runs today

The short story is the engine now has 2 tanks through it, around 30 minutes run time. It runs well, as one would expect. I ran 3 different Pattern size props, 18x12, 18 3/4x10 and 20x10. All ran better than I expected and better than other engines I have been playing with for the same application. The 18 3/4x10 was an 18.1x10 originally; I extended the tips to tame the Webra 160 years ago so it was a natural to compare.....turned at 8300-8400 on the bench which is about 800 rpm more than the Webra ran the same prop. The 18x12 turned similar rpm but needed leaner needles to do it. A little lower load than the 18 3/4x10. The 20x10 was the real surprise for me, turning a much faster than anticipated 7800. You could hear air ripping and this gas engine is still new. I expect a little better after a few gallons

BUUUUT!! The proof of the pudding as they say...... I need to see what it does with any of these props in the air. If it bogs down anywhere for example. Also, we won't know how it runs in hot conditions until next summer, unless one our mates from down under gets some hot runs earlier

Very good field (bench) manners. After setting up and running the rig initially, hot starts were no more than 2 flips. Smoother than expected for a longer stroked engine. But OS should be expected to get all of that right.

The factory needles (1 1/2 HSN and 1 LSN) probably will work okay for a light load such a 18x8 as they quote in the manual. They were a little too lean for my props. I ended up at 1 3/4 on the HSN and 1 1/8 on the LSN. At these needle settings even the 20x10 displayed instant accel from extended idle.

I am fairly pleased with this choice so far. I will be putting into Temptress next week and get some serious break in in the air and hopefully the weather will cooperate.

papaone

Hello Matt

Which exhaust system do you use, tuned pipe and header ?

Is it Hatori header ?
http://www.hatori-models.co.jp/HP3/k...301.2551e.html
Thanks

MTK

I massaged a Hatori header intended for the OS 160 to do this job. Didn't know that Hatori already has a header for the 33GT, which is great news. Papa you would need the 2301 header. I used the ES40G pipe but the ES30G would work fine. Distance from center of head to baffle was set at 28" similar to the SAP 180HP I've been using.

Fuel is Aviation gasoline mixed 50:1 with Bel Ray MC1 motorcycle racing oil ....100% synthetic. I use Aviation gasoline because of no smell and stability over long periods. But no reason why premium gasoline for cars wouldn't work.

Before getting ahead of myself, I really need to get the engine in the air and see what the performance is in a real application. Stay tooned

nonstoprc

My Feedback: (90)

I probably would try the OS 33GT if I have not made transition to motors/escs/batteries. I once tried the ZDZ 40 FAI on a gas pattern plane and was not impressed by its power much. The maintenance required is just as much as the glow version. Do to discourage the idea but if this 33GT can pull off with pattern application, it is a good thing to know. Glad that you are actively seeking the best.

MTK

On TIMBLE's suggestion I contacted the Magni Brothers about a new purpose built engine and to my surprise, Claudio answered. The question was " would Mintor be interested in building an engine with the top end of a 55cc and the bottom end of their 33cc, resulting in a 43cc engine.....Signore Claudio politely answered not at this time due to other projects currently in progress. But perhaps in the future, it could be considered, for F3A"....

So I take this to mean wait and see how this sector of the market plays out over the next year or two.

MTK

I have the 33GT roughed in in my Temptress. I needed to drop the mount vertically about 1/8" and canted it left about 7 degrees in order to make everything fit. It is a tight squeeze since Temptress is a rather narrow fuse by today's standard in Pattern. I'll take a couple snaps tonight when I get home. No provision for a nose ring yet. I need to simply run the beastie to see.

TimBle

Ok Don't everybody go mailing them now. Don't want their time taken up answering emails when building beautiful engines takes priority

I am very confident they will built one. It may not be as per your suggestion but a pattern engine makes a lot of sense. Gassers for RC are very much an area where an engineer can sink some creativity and refinement into.

MTK

BTW is there a source where one can buy headers? Both of the headers you show are needed items since many people use the DLE55 and DA 50 as well, me included.

choihjin

My Feedback: (1)

Dear Matt K
Here is one in Florida in USA:
http://www.gravesrc.com/HATORI_HEADE..._p/hat2301.htm
The header for DLE 30 is same one for OS GT33 (HAT 2300 and 2301).
Seached in Google as 'Muffler GSA30 26~30CC / HEADER ZENOAH 26 DLE30'.
Good Luck

CustomPC

I have ordered Hatori and other hard to find Japanese items from http://www.ishiimokei.com in the past with good results

MTK

Thanks...ordered it. Needed a back up anyway

TimBle

http://www.radarrc.com/index_eng.php

papaone

Hello

Did anybody use the muffler GSA 30 for OS GT 33 ?
On Hatori page it's written "Mufflers for Gas Engines targeted to reduce noise without sacrificing performance"

I think tuned pipe (as ES 30 G or 40 G ES Composite) gives better rpm ?

Claude

http://www.hatori-models.co.jp/HP3/k...air/2300e.html

MTK

I have not used any muffler on any of my gasoline engines so I don't have a first hand comparison. But judging from power/rpm numbers people are quoting for specific props on muffler, a pipe gives considerable boost in output over the quoted numbers. A pipe enables higher pitches to be used for the same rpm and diameter. OR larger diameter for the same pitch and rpm, but you will have to be careful with larger diameters because noise can increase fast.

A pipe also significantly reduces the noise footprint over mufflers. Expect to be drowned out by any muffled engine flying. Couple a pipe with a 3 bladed prop and a soft mount and you will hear even a larger difference in noise footprint.

I promised photos but just couldn't get to it last night. I may get to it tonight

MTK

I promised photos but just couldn't get to it last night. I may get to it tonight