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My SQ2 Mods

B

Barnstormer

Decided I'd post mods I make in here going forward. I've already posted about the TK1 suspension and T3 suspension in different posts.

So this first post here will be about getting cylinder head temps down. Being the prototype SQ2 mine has a cowling that is unique to my plane, but this might still help others. From the beginning my problem has been with No. 3 cylinder. When on a sustained climb it would head north of 400 quickly so I'd have to slow to about a 200 or 250 fpm climb. Around here the only sustained climbs I do are to cross the Turnagain Arm (3,500 feet) and to cross the Cook Inlet at the Forelands (5,500-6,500 feet) so it wasn’t a huge problem-just annoying.

First thing I did was inspect all the cylinder baffling to make sure it was in place. Then I sealed up 99% of leaks between the baffling and the cowl (not much help really).

Increased the carb jet size. That helped delay the temperature rise but didn't do much else.

About all that was left was to install cowl louvers. I really like the monster ones on the new XCub but alas they wouldn't work on my cowling and are crazy expensive.

After much searching I located some that would work and installed them. Bingo! That dropped No 3 in line with the others and now I can do a sustained 750fpm climb with CHT holding at 395. What is really interesting though is what must be going on inside the cowling regarding airflow. When I first start the engine and let it warm up No 3 climbs far faster then the others, in the same manner/pace it did when climbing before putting the louvers on. Yet as soon as I'm flying No 3 falls right in line with the others.

I got the louvers from Flyin’ Miata.

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I retarded my timing 2 degrees and now all my temps are under 390. My number 3 as well has always run hotter than the rest. It’s still the one I watch on hard climbs but after adjusting my timing it’s helped dramatically

akt
 
Did you put them on both sides or just the one? Looks good, will be barely noticeable once you paint them :)
 
Timing. Thanks for that post. I forgot I pulled the manifold hoses off the PMags long ago because the hyper advanced timing at cruise caused No 3 to run too hot. I'll have to hook them back up and see if that problem is solved as well, get me a little better gph if it is.

Both sides. And built some replacement flat plates in case I need the extra heat in the winter.
 
I think the louvers look good on the plane. Any reason the SQ don't have open cowl cheeks like on a cub?
DENNY
 
I think the louvers look good on the plane. Any reason the SQ don't have open cowl cheeks like on a cub?
DENNY
I certainly don't know the answer to that, but have wondered the same thing. Of course I don't know if it would make a difference or not. I'll try and remember to ask next time I see Wayne Mackey.
 
Phil,
I don’t post much on the other thread but on the topic of Helios.....SOAR Aviation in Bolivar, MO. Talked to them at OSH. They offer training/checkout in a Helio. Seemed pretty reasonable per hour. Explained all the models and showed me examples parked near by. They seemed to have a thumb on most of the flying Helios. They are pigs to push on the ground:???: Good luck with the hunt
 
Mike schooled me on this today. The back side of #3 won't flow air through the cooling fins. The baffle needs a spacer to allow air to flow down and reach the aft lower quadrant of the cylinder. Here's a pic of the front of #2, which is the back side on #3. The second pic is the front of #1, or the back of #4. It explains why #3 gets hot on some planes. Does your aft baffle allow some air space on the back side of #3?
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Sent from my iPhone using SuperCub.Org mobile app
 
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Mike schooled me on this today. The back side of #3 won't flow air through the cooling fins. The baffle needs a spacer to allow air to flow down and reach the aft lower quadrant of the cylinder. Here's a pic of the front of #2, which is the back side on #3. The second pic is the front of #1, or the back of #4. It explains why #3 gets hot on some planes. Does your aft baffle allow some air space on the back side of #3?
154a4d443844c62fe99b7aa3744b26c2.jpg
be5cb795f199f8fa1a83752bdf39da89.jpg



Sent from my iPhone using SuperCub.Org mobile app

not that I came up with this,

but I always wondered why some Lycoming style baffle installations had a spacer on right rear cylinder, but not on left rear....

by studding cylinders, noticed one side pf cylinder head is not the same as opposite side...

when it's installed as a left rear cylinder, the cylinder has FINS all around to let air FLOW from TOP to & through Bottom fins

right does not, it's blocked by head/no fins at center...

so that = NO flow for top rear to/through bottom rear fins on #3....

that spacer on cylinder #3 is important...
 
Hmmm, very cool info. I'll take a look in the morning. Thanks Stewart and Mike!

Mike schooled me on this today. The back side of #3 won't flow air through the cooling fins. The baffle needs a spacer to allow air to flow down and reach the aft lower quadrant of the cylinder. Here's a pic of the front of #2, which is the back side on #3. The second pic is the front of #1, or the back of #4. It explains why #3 gets hot on some planes. Does your aft baffle allow some air space on the back side of #3?
154a4d443844c62fe99b7aa3744b26c2.jpg
be5cb795f199f8fa1a83752bdf39da89.jpg



Sent from my iPhone using SuperCub.Org mobile app
 
I like the louver idea. Louvers have served well on my 180. I wonder if anyones's crafted a cowl flap on an SQ cowling?

Re: the baffle. Here's what mine looks like. You can see the baffle is boxed to move it away from the back of #3. The top view shows about 3/8" of space behind the cylinder.
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Sent from my iPhone using SuperCub.Org mobile app
 
I think the Grumman Tiger baffles built a little “box” around that part of the fins. I’ll try to google a pic. I’ve got a couple of washers under that bolt on my O-320 as well, dropped my #3 in line with the others in cruise. In climb my #2 is the highest and probably for the same reason.

EDIT: I couldn't find the particular picture I was looking for. Google for "baffle mod" as well.

Lycoming_O-320_cover_removed.jpg
 
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Looks like I do have a standoff baffle on No 3 cylinder.

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The SQ-2 is now wearing a pair of Carbon Concepts Skis w/ Airframes Alaska Grizzly Claw Ski Drag.


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The pedestal is taller then most other skis. The sides of the skis are turned up helping the ski not catch an edge while the plane is turning.


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The bulk of the rigging was purchased from Stoddards. The brake hoses and fittings from Alaska Rubber.
http://www.stoddardairparts.com
http://alaskarubbergroup.com


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The blue brake line fitting on the Grizzly Claw comes installed loose from Airframes so be sure and either replace it with a different one you prefer or tighten it. A 5/32" Allen wrench is required to remove the cylinder so the fitting can be tightened.


The next weather day I do my first ever flight on skis!


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nice.

but, those ski brakes are still an unholy marriage of levers & hydraulics and 80% more size weight than they need to be... like an unreduced fraction... I've exchanged emails with them, but wasn't able to get through to them....
 
nice.

but, those ski brakes are still an unholy marriage of levers & hydraulics and 80% more size weight than they need to be... like an unreduced fraction... I've exchanged emails with them, but wasn't able to get through to them....

Did you talk to Abe? He was very receptive to ideas and changes when I was testing the T-3.


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You’ll really like those skis. Once you get a good feel for them try pushing some forward stick into it to make some really tight turns. Either direction.

Hopefully we will get some more valley snow soon and I’ll have mine back on. Skis are fun.

Mike, that “Unreduced fraction” line put a smile on my face.
 
What parts did Airglas have that you needed?

The crust cutter through the spring is a no-no. Guys still do it but they usually sleeve the cable so it doesn't saw on the spring.

I wouldn't trust those zip ties holding your brake lines. Cold temperatures and crusty snow will probably break them.
 
Bungees instead of springs was what I was primarily looking for that I couldn't get elsewhere.

I was told the cable through the spring is the front limit cable. He put it through the spring so if the spring has a catastrophic failure it won't slap into the propellor. What can it be sleeved with?

Yea I figured the zip ties won't like the cold. Haven't come up with another solution yet. Kind of a temporary solution anyway as once my mechanic gets back from vacation we are going to change out the fittings on the ski drag from No 4 to No 3 and use a No 3 hose to match the other brake hoses. Any ideas would be appreciated.

Also, any thoughts on what's best to put on the top of the skis where I'm likely to step from time to time? Being an ex-Stearman driver my mind went straight to wing-walk paint.

What parts did Airglas have that you needed?

The crust cutter through the spring is a no-no. Guys still do it but they usually sleeve the cable so it doesn't saw on the spring.

I wouldn't trust those zip ties holding your brake lines. Cold temperatures and crusty snow will probably break them.
 
Bungees instead of springs was what I was primarily looking for that I couldn't get elsewhere.

I was told the cable through the spring is the front limit cable. He put it through the spring so if the spring has a catastrophic failure it won't slap into the propellor. What can it be sleeved with?

Yea I figured the zip ties won't like the cold. Haven't come up with another solution yet. Kind of a temporary solution anyway as once my mechanic gets back from vacation we are going to change out the fittings on the ski drag from No 4 to No 3 and use a No 3 hose to match the other brake hoses. Any ideas would be appreciated.

Also, any thoughts on what's best to put on the top of the skis where I'm likely to step from time to time? Being an ex-Stearman driver my mind went straight to wing-walk paint.

reeve has bungies

you put vinyl hose over cable if in spring
 
I’ve had a roll of no-skid tape for long enough that I can’t recall where I got it. Mine is aluminum tape with about an 80 grit surface. It works great on skis.
 
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