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Polini 303DS

Posted: Fri May 12, 2023 6:03 pm
by Mountain Cat
Thinking about selling my Polini 303DS, everything ordered from Chris. It might be too light for my purpose. Includes everything, the whole ball of wax. 304-847-5723

Re: Polini 303DS

Posted: Fri May 12, 2023 11:32 pm
by LA F2 Flyer
Has it been run in?

Re: Polini 303DS

Posted: Sat May 13, 2023 8:05 am
by Mountain Cat
No never been started. But all polini's have been test run at the factory. The only way I can use it is talk Chris into building an engine mount that moves is forward another 8"-10". The problem is not the engine but, it's light enough to not let the CG move forward into the range. Only way to move the CG towards the nose is to move the engine forward. Without adding excess weight.

Re: Polini 303DS

Posted: Sat May 13, 2023 10:54 pm
by Mountain Cat
As it turns out, I was working with limited information that was 30 yrs old. I won't make ultralight weight, but that's OK. I have a PP license. The 303DS will take some minor adjustments but will work out I think as of now.

Re: Polini 303DS

Posted: Sun May 14, 2023 7:17 pm
by LA F2 Flyer
Good to hear. It simplifies things a bit for you!

Re: Polini 303DS

Posted: Sun May 14, 2023 8:57 pm
by Mountain Cat
I tried to make Pt 103 but just can't pull it off. Considering I need a bigger tail wheel, also have individual flaps plus ailerons, along with bigger tires, its just more than Pt 103 will allow. So E/AB it will be. Still fly it as a LSA pilot though.

Re: Polini 303DS

Posted: Mon May 15, 2023 10:31 am
by LA F2 Flyer
How far past 103 are you, out of curiosity?

Re: Polini 303DS

Posted: Mon May 15, 2023 3:57 pm
by Mountain Cat
About 20 lbs. But registering it has some advantages. Can use bigger tires if wanted, more fuel cap if wanted. Downside is will require a BFR every two years. Around here, the FAA doesn't bother with experimental aircraft unless you do something stupid. And a BFR keeps you from developing bad habits.

Re: Polini 303DS

Posted: Tue May 23, 2023 9:10 pm
by Mountain Cat
Polini 303DS is just too light for my airframe. Putting it on Barnstormers. CG will not come in limits without serious rework.

Re: Polini 303DS

Posted: Thu Jul 20, 2023 9:41 pm
by Mountain Cat
Well, got tired of waiting on a new engine mount from Chris. Decided to reinstall the engine/mount and do whatever is necessary to bring CG into range if possible. When he does get it made, then this winter I'll change it out. This way I can get the engine dialed in and running good. Evidently he is covered up in work and has little spare time. Maybe supply shortages, backorders, etc. This day and time, who knows what will happen next.

Re: Polini 303DS

Posted: Sun Aug 27, 2023 3:59 pm
by Mountain Cat
Installed the new 303DS, run it for 20 min to verify everything was working (it was) and then removed it and put it back in the factory crate. If anybody needs one, $3000 for the complete package including prop, mount and gauges.

Re: Polini 303DS

Posted: Sun Aug 27, 2023 7:11 pm
by LA F2 Flyer
I might be interested in that engine. Did you happen to run it up to max static RPM and check the thrust? (As you know mine doesn't see to rev up to where it should be...)

Would love to see some pics.

And do you have any idea if it fits the same engine mount as the Thor 200?

Also, what does it weight all in (minus prop)?

Re: Polini 303DS

Posted: Sun Aug 27, 2023 7:55 pm
by Mountain Cat
I briefly ran it up to about 5500 and still had more throttle left to go. Checked both ignitions to verify they were working. Total time was about 20 minutes. The prop weight is less than 1 lb. Total engine weight(flying weight) was 65 lbs. According to Polini, the 200, 250 and 303 use the same mount. But I have all the mounts to bolt it to a Badland. I got the package from Chris ($7500) plus ordered the bleeder valves, and 90 deg thermostat housing. I also have the extra senders for EGT, CHT, and water temp. And the Polini gauge that Chris sent. But depending on where you are, shipping is expensive in todays world. You would be looking at 3 boxes.
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Re: Polini 303DS

Posted: Mon Aug 28, 2023 3:28 pm
by LA F2 Flyer
I will say it's very tempting! My only concern is that it might put me over weight...my current engine (by itself, no prop, mount etc) weighs in at about 39 pounds. (When you say "flying weight", what exactly does that mean? Is that including the mount, bolts etc?)

The other concern is that you didn't rev it over 5500...probably pure paranoia on my part, but that's why I want to swap mine out - it won't rev over 5500RPM. But you did say it felt like it had more to give...

Re: Polini 303DS

Posted: Mon Aug 28, 2023 4:25 pm
by Mountain Cat
Flying weight is mounted on the airframe ready to fly w/ all fluids. If it don't sell, this fall I'll mount it on my trailer as a test stand and have it running. Easier to sell if someone can run it and check everything out before they buy it. I didn't go over 5500 rpm due to it wanting to pull the plane forward along with my ATV. But mounting it on a test stand means pick up only.

Re: Polini 303DS

Posted: Mon Aug 28, 2023 7:48 pm
by LA F2 Flyer
Oh, that makes sense about not going over 5500. I may need to re-weigh my plane and see how much leeway I have. I wouldn't mind the extra horses nor the watercooling.

Re: Polini 303DS

Posted: Mon Aug 28, 2023 7:56 pm
by Mountain Cat
The fuselage ready to fly, wings, tail, instruments, and all your goodies needs to be under 180 lbs. That would leave you 70+ lbs to play with.

Re: Polini 303DS

Posted: Thu Sep 21, 2023 5:09 pm
by mrpilotron
Where are you located? I'll be shopping for an engine in the near future.

Re: Polini 303DS

Posted: Thu Sep 21, 2023 7:07 pm
by Mountain Cat
Peer has already (stolen LOL) errr, I mean bought it. You might ask him if he is in the market to part with it.

Re: Polini 303DS

Posted: Thu Sep 21, 2023 7:46 pm
by Badland-F5 Pilot
Mountain Cat wrote: Thu Sep 21, 2023 7:07 pm Peer has already (stolen LOL) errr, I mean bought it. You might ask him if he is in the market to part with it.
With an appropriate mark-up I'm sure he'll sell – oh wait, I've already seen pictures of it mounted and the fun he's having with all you included, plus orders from Aircraft Spruce & Specialty Company and Amazon arrived today. Ah, maybe he won't sell it after all. It was an excellent deal.

Re: Polini 303DS

Posted: Thu Sep 21, 2023 9:04 pm
by Mountain Cat
I hope it's just what he wanted. I could not use it for my bird so why keep it. It is a powerful engine. I didn't change anything in the carb so it's just like it came from the factory. I am sure he will have to adjust, re-jet for his conditions. I thought it might be running a little on the rich side but didn't run it but only 20 minutes or so. It would be hard to tell in that time period. I am at about 2500' MSL here at home and 2 strokes are finicky anyway. It's supposed to have an alt adjusting carb but that is what Polini states.

Re: Polini 303DS

Posted: Fri Sep 22, 2023 11:08 am
by LA F2 Flyer
Now that the "theft" has been completed, I have indeed started the installation! Hoses arrived from Amazon, a nice selection of nuts and bolts (and Adel clamps) arrived from Aircraft Spruce, and the fun has begun!

The radiator location has been determined and the hose install has started. I've also bent an aluminum bracket for the battery, which will end up between the rudder pedals. The throttle cable has been installed and confirmed to return to idle. That's as far as I've gotten. The biggest struggle will likely be finding a location for the starter/ignition box. It's a pretty big bugger.

I'll still need to buy more aluminum flat stock to make the radiator mounts, and a remote (cable) choke for the carb. Once the cowl is back in place (assuming I can make it fit) I won't have easy access to the choke lever.

Allen answered a question I was going to ask - what is your current field elevation? I'll definitely need to rejet as I am about 2000 feet below you.

Hopefully I'll find some time to work on it again soon! I will say, it's been nice to have a new and intensive airplane project!

Needless to say, I won't be selling this engine just yet. :)

One question for the group - how critical is it to get the expansion tank WELL above the cylinder head? I don't have that much room to work with, so my fill line on the tank may only be an inch or two above the top surface of the cylinder.
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Re: Polini 303DS

Posted: Fri Sep 22, 2023 11:19 am
by Mountain Cat
Looking at the picture, 11;00 O'CLOCK IS WHERE i had installed it. Looks like you might have room. Of course that will require an access hole in the cowl.

Re: Polini 303DS

Posted: Fri Sep 22, 2023 1:03 pm
by LA F2 Flyer
Thanks Allen. Did you just have the cap protruding? I don't want to go too high over the firewall.

I am actually going to need a few extra holes in the cowl if I intend to use the one I currently have.

Re: Polini 303DS

Posted: Fri Sep 22, 2023 1:10 pm
by Badland-F5 Pilot
LA F2 Flyer wrote: Fri Sep 22, 2023 11:08 am Now that the "theft" has been completed, I have indeed started the installation!
I love it!

Re: Polini 303DS

Posted: Fri Sep 22, 2023 3:01 pm
by Mountain Cat
No, the cap was about 3/4- 1" below the cowl. I used a fabric inspection hole cover, those 4" alum disc, to cover the hole. easily removed and put back and can be painted to match. Very very good, last long long time, as my friend Ho Ching once said.

Re: Polini 303DS

Posted: Fri Sep 22, 2023 4:46 pm
by LA F2 Flyer
And Ho Ching knows his stuff, I'm sure. haha

I just wonder if it's really necessary to hang quite as high above the rest of the cooling system as Polini suggests. (If I were to do so, it would be five inches above the cowl.) As it stands now, my fill line (middle of the reservoir) is likely to be about an inch below the top coolant hose.

Do you think there's any harm in my current placement?

Re: Polini 303DS

Posted: Fri Sep 22, 2023 8:15 pm
by Mountain Cat
The expander tank is basically a relief tank for over pressure. The main cause for concern is bleeding ALL the air out of the system. Failure to do so is a cooked engine. The only air in the system should be in the expansion tank (1/2 full). With no leaks, the little tank will take the excess fluid due to heat expansion of the fluid and then when cooled allows it to return to the engine.

Re: Polini 303DS

Posted: Sat Sep 30, 2023 2:09 pm
by Mountain Cat
Didn't get any calls on the SkyRaider/Mountain Cat from Barnstormers. So I suppose I'll make a new cowling, add some mountain bike brakes and find an engine. Also will get my PPL current. Or with the new rules, or just drop to a sport pilot license. And go thru the airworthiness Insp. Got to have something to do this winter.