Author Topic: MT Propeller  (Read 4410 times)

Doug Johnson 1

MT Propeller
« on: January 24, 2019, 05:31:14 PM »
Larry Schlasinger the MT prop representative contacted me today and said they are looking for someone that needs a prop for their 295hp GO-480.

They need to do a field approval on at least one if not two or three to work toward a full blown STC. They are looking for someone or more, here in the lower 48 states because they are located here in the Midwest and it is just easier for them, but  they are not ruling out the guys in Alaska either.

I think this is probably a real good deal for someone that needs a prop they will walk them through the field approval and they will get to keep the prop. It's not free but there is no extra cost and much cheaper than a Hartzel and you will save a lot of weight.

Larry says they have a two blade prop approved for the 245hp GO-435 and the 270hp GO-480

Now they are looking at the GO-480 at 300 Hp and they also believe because of the thicker chord of composite blade which causes it to go supersonic at a lower rpm, that they will need to go to the 3 blade at 95" instead of a 101" or 103" 2 bladed prop, but they will look at that as well also a reversible prop for float plane use is contemplated and will be looked at.

They are looking at the 340hp GSO-480 as well. Anyone with one of those?

I mentioned the difference in oil pressure that was brought up in an earlier post and Larry said he had asked their engineer about it and it was new to him because you would use the Helio prop governor. I believe it is being looked into.

Larry says they would like to do this as soon as possible and by summer time at least.

So contact Larry Schlasinger directly at 612-619-5782 but then, when you do this you have to keep the rest of us in the loop.

check out this link to richs post  click on

click on

click on
« Last Edit: September 26, 2021, 09:37:00 PM by Doug Johnson 1 »


Re: MT Propeller
« Reply #1 on: January 24, 2019, 08:01:41 PM »

I put a request on the site asking 295 owners to give us the information on their prop situations. The thought was to have some accurate informaton going forward to have MT know that this is worth their while to consider, and of course keep the cost down if they have potentially 4-5 dozen over time.

Obviously I'm due (#1295) on blades but a new and improved prop is preferred. Paul (#1434) tells me his prop was overhauled ~4 hours ago, however, blades may be done from the accident.

Would you be able to entice more owners to fess up?

By the way, Dave Maytag has also indicated that he is willing to help out with any information required from him. He also has worked on a MTV9 reverse set up for his 250 with the russian radial. Anyway, Heilo is on board.


Re: MT Propeller
« Reply #2 on: January 25, 2019, 06:12:07 AM »
I have been in contact with Gerd at MT and they are now in the development of 3-blade options for Helio 295, he has all the specs and current Hartzell info. I have spoken to Larry as well and he says that in Canada no field approval is available thanks to Transport of Canada, they are more strict.

The gear box for the GO, IGO, GSO-480 is 270 PSI, they have seals, bearings and fasteners already tested to 320 PSI. The blades they propose for 295 application in the 98" length are not supersonic at 2175 RPM with the 3-blade option, when certification was under going with the DO-27 GO-480-B1A6 is when some flight testing resulted in supersonic blade tip speeds, but since has been resolved.

One more thing to take home with you is that operators that fly into the bush in Alaska with 180/185 and 206 airplanes have noticed the MT blades do not hold up well off of gravel and sandbar uses is what I'm told. Continued use in these areas have been a bit of a sore spot with owners.

They already have a 2-blade option for the Dornier DO-27.

« Last Edit: January 25, 2019, 09:43:26 AM by tailhook »


Re: MT Propeller
« Reply #3 on: September 03, 2019, 10:38:55 PM »
Any update on this?  Is MT actually working on a prop for us?  Every time I walk around the airport and see these nice new MT props on peoples planes with that new nickel leading edge that is nearly impervious to sand erosion and small pebble nicks I start to get jealous and hope.  With every passing day and new nicks on my freshly overhauled blades along with a weight and balance that says I really need to lose 20lbs off the nose I get closer and closer to be willing to fork over the money.

Is this actually moving forward? 


Re: MT Propeller
« Reply #4 on: September 04, 2019, 08:11:49 AM »
that in Canada no field approval is available thanks to Transport of Canada, they are more strict.

They are called LSTC.  Limited STC for one airplane.  A different name for a field approval for one aircraft.  TC being the type certificate.  STC a supplemental to the type certificate.  LSTC a limited to one aircraft supplemental modification to the type certificate.

They can be delevered by your local Transport Canada office, or trough a delegated engineer ( an engineer that have the authority to sign as if he was Transport Canada )

I don't know about field approval in the States, but it looks quite similar to an LSTC.  For import from the USA to Canada on a modified to original TC, a US field approval could be asked to be change to a canadian LSTC.  The field approval data could be used, but the paperwork must be the same format as a canadian LSTC


LSTC, STC and RDC approval certificates specified in AWM Chapter 513 should be used by Delegates for all modifications and repairs not covered by a TC. The certificates used should be those provided by the regional offices in paper or electronic format, or if developed by the Delegate the certificate must be indistinguishable from a certificate issued by TCCA. Electronic templates provided by TCCA, or certificate photocopies may be used to generate certificates.
« Last Edit: September 04, 2019, 08:39:56 AM by Louis »


Re: MT Propeller
« Reply #5 on: December 30, 2020, 11:04:39 AM »
Any of you fellas know how much a 96" 3 blade Harzel weighs? (Hc-b3z20-1/10151cn-5)  I'm working with MT Larry on getting a field approval done for their 98" 2 Blade.
He also stated that the feds are tightening down on field approvals and this route may not be an option in the very near future.

Doug Johnson

Re: MT Propeller
« Reply #6 on: August 11, 2021, 01:37:00 PM »
Here are some photos of the the two blade 98" MT prop as it arrives. and 2 photos of the 96" prop on the a/c. I understand that the 'Helio Alaska" guys have done some pull testing I was hoping to get some numbers to post.

I will share Abe's email that he sent.

We just got the MT prop on the Courier and have been trying it out. It feels similar in performance so far, but we don't have enough time on it for a complete evaluation yet, so the jury is still out. It was a 34lb weight reduction being wood/composite instead of aluminum and 2 blades instead of 3. It is also significantly cheaper than the Hartzell when comparing full replacement costs between the two. Time will tell on how it holds up to gravel wear, etc. We were able to get a field approval on it at 96" but were not able to go longer due to that being a limitation on the TCDS for a H-295. Benny was able to get a 98" version field approved since he has an H-395, and it technically allows up to 101" max per the numbers in the TCDS. Mostly it was just matched to the original size to maintain ground clearance and noise factors for the field approval. I had inquired originally about the 3-blade MT as well, but their recommendation was this setup as the hub was already previously evaluated on the Dornier GO-480's in the past, so it was ready to go for the spline shaft setup on the GO-480, and the blade profile they picked is the widest cord blade they make (and different from the ones they used on the Dornier configuration, which were narrower), so it should still have a lot of bite even though it has one less blade. This blade is a shorter version of what they typically use on large aerobatic radials like Yak-52's and Sukhois, from what I understand. They were anticipating that performance should be equivalent to the original 3-blade. I am still curious if a 3-bladed MT would yield some additional performance, but the cost would also be higher, and weight reduction would not be as significant. So it's hard to say at this point. We're just gonna put time on this one for now and see how it does.

I've attached a couple pictures of MT prop on the airplane for you.

Abraham Harman
Helio Alaska, Inc.

Thanks for the info, Doug

« Last Edit: August 11, 2021, 02:13:14 PM by Doug Johnson »

Jason Stephens

Re: MT Propeller
« Reply #7 on: August 12, 2021, 10:25:20 AM »
Has anyone talked to David Maytag about what prop he used when he had the M-14 on his Helio?  I assume by how it looked it was an MT.  Maybe he would have some comments as far as ground clearance. 

Exciting to finally see an MT on a Helio and know there is a legit alternative.


Re: MT Propeller
« Reply #8 on: October 25, 2021, 05:40:21 AM »
My thoughts on the MT propeller after 10 or so take offs and landings.
It spools up fast and stops alarmingly fast when the mixture is pulled.
The sink rate when you are full flaps and behind the power curve is not nearly as terrifying, its almost docile. Probably like how an H-250 lands.
560 lbs of fuel and my fat ass broke ground at around 220'. I could only pull 3250 rpm and will need to flatten it out so the numbers should get better, gaining about 13Hp.
It was fairly easy to install however the service and instruction manual could be better.
I still need to test the cruise but I wanted to get the low end dialed in first and install gear leg fairings.
Larry is super easy to work with and he always answers his phone.
That being said I have a bunch of Hartzel blades for sale. I probably should have sold them first before I posted this.



Re: MT Propeller
« Reply #9 on: October 28, 2021, 07:47:44 AM »
Can I ask what was the final cost?

Jason Stephens

Re: MT Propeller
« Reply #10 on: October 28, 2021, 10:31:33 AM »
Thanks for the update.  I wonder if the lower mass will have any effect on gearbox longevity.



Re: MT Propeller
« Reply #11 on: October 28, 2021, 10:24:39 PM »
The field approval cost was around 3k for Larry to do it and the prop cost at the time was $18500.


Re: MT Propeller
« Reply #12 on: October 30, 2021, 08:56:19 AM »
Thanks for the update.  I wonder if the lower mass will have any effect on gearbox longevity.

Maybe.  Logically.  But never as much as changing your oil at 20 hours instead of 30


Doug Johnson

Re: MT Propeller
« Reply #13 on: October 30, 2021, 09:13:10 AM »
Louis, serious question, I changed my oil every 25 hrs when I only had a screen but after converting to a filter and began using multi-viscosity synthetic oil I went to 40 hrs and if it was inconvenient in the middle of a long cross country I didn't worry if it approached 50 hrs.

Was I seriously mistreating my engine or just a little bit.

I just had a thought, it's going to be a little more difficult to identify Helio models now and the two blade doesn't look quite as hot, but if you know a little bit about props the two blade props length is even more obvious and the wide chord make it look like there's a lot of engine behind it.

The prop experts that i've talked to in the past claim that a two blade prop is more efficient than the 3 blade prop.

Larry Montgomery claimed that the Factory had a 105" inch two bladed prop (developed mainly for seaplanes, but there was a lot of erosion from the water spray), that had a lot more thrust than the 3 bladed prop, and if used on land it would vacuum up a lot of debri when sitting still you had to be really careful with it, and all runups had to be done while moving and minimal time while idling particularly on gravel strips and beaches.

I saw a patent for a one bladed prop with a counterweight in a magazine article years ago can't remember much about it. It obviously never became very popular.
« Last Edit: October 30, 2021, 10:05:41 AM by Doug Johnson »


Re: MT Propeller
« Reply #14 on: October 30, 2021, 08:29:24 PM »
Many are saying that a two-blade prop on a 185 pulls more than three blades.... with the same engine.  Since some of the three blades 185 have a more torque engine.  Those questions are difficult to answer since the performance is just not only the static pull.  If it was, attaching a balance to the aircraft would give you a straight an easy answer.  But it is more complicated than just the pull power at static.  It is also a question of efficacity when you start to gain some speeds.  How much it does pull when around 45 mph.  How efficient it is on cruise.  How it transform drag to longer landing distance ( i am never able to outperform the 250 with the 295 when landing.  Don't ask me why, even at same gross weight.  I have a tendency to keep some power with the three blades.  Resulting in double landing distance than the two blade 250 ).  There was a 295 with blades as long as a 391.  Own by M. Bouthillier.  Some say it was performing a lot better than the regular 295.  I don't know how a two blade vs a three blade would perform on all the various speed of a flight.  And since we are talking about a MT, it is another shape.  When this subject started, i was looking for how well a MT perform on a Seebe equiped with a 480 with a MT, two or three blades.  I did not find enough data.

About the oil.  Usually, the oil we put in our engine are formulated for the combustion engine part.  Not for a gearbox ( transmission ).  In cars, the oil in the transmission is many times thicker than the one in the engine.  The tremendous force between the teeth of th egear of a trsnmission does destroy a regular engine oil a lot faster.  Some cars have been made with the same arrangement as our engine, same oil going for the transmission and the powerplant.  In these cars, you have to change the oil a lot more often than a regular car.  Look at our oil after 20 hours.  Feel it between your fingers.  The viscosity is like nothing when it was 15 hours.  Lycoming invented the PLUS for a better lubrification on the cam  of some of their more fragile engine.  And for the gearbox engine.  Viscosity is the same when new.  But the PLUS is supposed to keep the viscosity a little longer.  It isn't a question of filtering metal dust.  It is a question of preventing it.  And there is nothing more effective to prevent two pieces of metal that rub together to destroy themselves than have a film of oil between them.  Good, clean, fresh oil.  Our engine are quite difficult to reman properly.  Parts are not easy to find.  The springs that put pressure on the cams are stronger than other engines since they have to work well over 3000 rpm.  Oil is cheap.  On the Supercub, the first 25 hours i need maybe only one quart to add.  If i want to bring my oil to 50 hours, i will start to put a quart per 4 hours of flight.  At the end, i will save next to nothing in quantities of oil.  The second 25 hours took almost 6 quarts added one by one as flying those second 25 hours.  But i will fly those 25 hours after the first with some oil that is not as good as one of the first 25 hours.  Neil convinced me that saving a few quarts of oil, is the best way to shorten the life of all the parts in the engine.  Since oil is easily available, parts are not, i choose to buy oil instead of a new engine.  So far, so good.

We have an engine with a cruze RPM around 10% more than a non geared engine.  So let's say that we are ok to change oil on a non-geared engine at 45 hours, then it does become 40 hours for a geared engine for the same revolution.  Add that we take off for two minute or so at more than 3300 rpm, where the maximum work is done, we can easlily figur out we can remove another 5 hours.  We are now at 35 hours.  Remove another 5 hours because we have a gearbox that use also property of the oil, we are at 30 hours.  And these numbers are made with the assumption that you are ok to change oil at 45 hours.  I am not ready for that even in a 180 hp straight engine.  I am not a chemist, but looking at my oil at 30 hours in the Supercub, i can see it ain't the same stuff as the oil at 20 hours.  I might be ready with the Cub because i can have an engine with one phone call.  But for the Helio, once you add the insurance, the fuel, the hangar, the mechanic, changing my oil at 20 hours will change next to nothing to the total cost of flying per hour.  And it might add some longevity ti that engine that is not so easy to find for a replacement.

But like the two vs three blades, we might never be sure if it does change something on the long run.  We can ask ourselves what kind of blades, what kind of oil, what temperature are we working. 

The only certitude i have: fresh oil is better than used oil.  If it was the contrary, the advice would be to never change it
« Last Edit: October 31, 2021, 07:14:46 AM by Louis »