OS 91 SZH engines from RC-mushroom

[Wayne]

Just a note, I ordered 2 OS-91 SZH's from www.rc-mushroom.com Friday December 30 at 4:00 PM for $235.00 each. I got concerned when they sent me an email back that night asking for a copy of my last credit card bill, a copy of my photo ID, and copy of the actual credit card. I may not be the brightest bulb on the block, but this sounds like a plan for Wayne to be feeding 5,000 Chinese college students Kung Pao chicken for a week. :bomb: I called them up to say what the heck, and they really would not move on their policy.

I ended up using pay pal to pay for them right away, and they shipped the engines out the same day.

The moral of the story is, be prepared to share your identity with them or use pay pal.

Now the good news. :D It's Monday mornging January 2 and the US Postal service knocks at my front door and drops off two SZH motors!

That's service for sure.

Wayne
www.flymha.com

[TerryBelanger]

Are the SZ'z with the pump out yet or are these just SZs without the pump?

[Wayne]

These do not have the regulator. :(

They will after I send them to OMI though! :!:

Wayne
www.flymha.com

[Jerry]

Terry,

The carburetor packaged with this early version of the OS91SZH is the 60M-C. The carb body is marked as a 60-M. There is a machined groove on the external lower carb throat that helps immediately delineate the carb case from the 60-M we are familiar with.

In general, the 60M-C is a 10.6mm bored 3 needle carb. Looks like they used the 60-M carb as a base, and ported it for the 3rd needle.

The pump/regulator version that will be available in a few months will also feature a 10.6mm bored carburetor, but will have the new OS pump and regulator fuel delivery system. There are internal differences between that carburetor and the 60M-C available now. So....it won't be as simple as bolting on the regulator / pump in a few months. The individual component availability might also be an issue, as I'm not sure OS has plans to sell the pump/regulator seperately as an economically attractive 'combo' aimed at such a goal.

So if you have your heart set on the new pump/regulator 91SZ you may want to consider waiting.

Jerry

[pilotError]

Do you think the addition of the pump will be all that different than the cline mod that OMI is doing?

[Jerry]

The OS pump regulator system offers a unique advantage. Due to the fact that the pump has high enough volume delivery pressure - no additional pressure is required. (as in the Cline or the PS system)

No pressure at all - muffler or unregulated crankcase pressure.

This means no tank expansion due to pressure. No checkvalves. No pressure relief "T's" No corrosive exhaust gasses in the tank. No more rotted clunk lines/tank fittings. No more eaten up Fuel Magnets.

The only thing in your tank is fuel. The tank is simply vented to the atmosphere.

I love my Cline setups from James at OMI. Ive never had a huge issue with pressure or rotted stuff because I don't mind doing some maintenance. But this is just basic info to decide on for yourself.

Jerry

[DavidH]

No checkvalves

The tank is simply vented to the atmosphere.

Jerry,
I may be wrong. but I believe there is a check valve on the line that is vented to the atmosphere. At least there was on the couple of SZ's I saw with the pump and regulator. But I guess this could be gotten around. By making a loop type trap in the vent line so the fuel would not pour out when the heli was inverted.

David

[Jerry]

David - you CAN put a checkvalve on that line if you wish, but its not necessary. Alan ran one on his SZ at Huntsville last year. I have the pump/regulator system installed, and I have never used a checkvalve. Why complicate the world with more physics than we need?

My line exits the top of the tank, and heads down to bottom plate where it just sits there wide open. Never so much as a drip unless I overfuel.

:glasses2:

Jerry

[DavidH]

Jerry,
Ok that is cool. I had just seen Steve's setup and at that time he was using a check valve on the vent line.

David