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View Full Version : Remove belly pod w/LH4000s?



JohnnyR
10-02-2020, 12:15 AM
Also posted this over at https://backcountrypilot.org/forum/remove-belly-pod-w-lh4000-s-24475#p342939 .

Were getting ready to install a set of Airglas LH4000 hydraulic skis on our PPonked C180 w/ 3-blade MT prop.Am wondering if we will need to take off our Aerocet belly pod (smaller than Cessna/Firman pods) or will the LH4000s provide enough flotation (1955 sq in) in all but the lightest/deepest powder to keep that belly from wallowing enough to affect performance? Sure would like to keep that cargo capacity for winter gear.
We will likely install the Burls tail ski.

supercrow
10-02-2020, 04:15 AM
Mine is a homemade pod, so for what it's worth. Have seen no problem in very light deep snow. Might be better with it on there. Am on 3" extended gear.

supercrow
10-02-2020, 04:22 AM
I don't think it will be in the snow in most cases.

stewartb
10-02-2020, 07:28 AM
Plenty of 185s have the big Cessna pod on skis. Fluffy snow that you sink into isn’t going to be your problem. For that you stomp out the run with snowshoes. Sinking into overflow is a different story.

DENNY
10-02-2020, 11:06 AM
A big tail ski is really helpful in soft snow!!
DENNY

alaskaoe
10-02-2020, 12:04 PM
51368
Of course it all depends on the snow but this was pretty deep unconsolidated snow right here. I wouldn't have wanted to be any heavier but the LH4000 skis did the job.

stewartb
10-02-2020, 12:10 PM
I am SO not ready!

JohnnyR
10-02-2020, 12:23 PM
A big tail ski is really helpful in soft snow!!
DENNY
I wonder how they do with non-lockable tailwheels.... (like my 180 has).

stewartb
10-02-2020, 12:30 PM
I have a Burl's Magnum on an 8" tailwheel and another on my BBW wide fork. I don't have shimmy problems. My lock is long gone.

JohnnyR
10-02-2020, 12:35 PM
I have a Burl's Magnum on an 8" tailwheel and another on my BBW wide fork. I don't have shimmy problems. My lock is long gone.

How’s it sit with 8.50’s on skis and the BBW w/tailski? Any prop clearance concerns when not on snow?

stewartb
10-02-2020, 01:01 PM
No prop clearance issue with my 86".

Have you flown the Wagon on skis yet? I don't know about LH skis but my AirGlides reflect the prop noise into the cabin. Holy cow it's loud. Thank goodness for ANR.

mam90
10-02-2020, 01:49 PM
Don’t miss working a big single on skis! That picture gives me the shakes!

JohnnyR
10-02-2020, 01:50 PM
No prop clearance issue with my 86".

Have you flown the Wagon on skis yet? I don't know about LH skis but my AirGlides reflect the prop noise into the cabin. Holy cow it's loud. Thank goodness for ANR.

No, not yet. That’s an interesting effect I hadn’t forecast. I wonder if the MT prop and Airglas materials will attenuate the noise. Will report.

mvivion
10-02-2020, 05:17 PM
Take LOTS of winter camping gear, a big grain shovel, snowshoes, etc.

The Burl’s tailski will be a blessing.....no lock required.

I ran a 185 on 3600 skis out of FAI and north. Had a Cessna pod on it a couple winters. Finally removed it, in very deep interior snow, it’d get you stuck. BUT that is a huge pod compared to yours and those 4000 skis wil float way better than the 3600s I believe.

But trust me, you WILL get stuck if you operate in deep snow much. It’s those multiple crusts that can really bite.....don’t ask how I learned that.

Go prepared to camp. When you get stuck bad, make camp FIRST, including a nice big fire. THEN work on getting unstuck. It may take a day or three.

Have fun!

MTV

JohnnyR
10-02-2020, 09:54 PM
I’m good with spending days in the bush in winter, but will try to exercise preventative caution & foresight!


Take LOTS of winter camping gear, a big grain shovel, snowshoes, etc.

The Burl’s tailski will be a blessing.....no lock required.

I ran a 185 on 3600 skis out of FAI and north. Had a Cessna pod on it a couple winters. Finally removed it, in very deep interior snow, it’d get you stuck. BUT that is a huge pod compared to yours and those 4000 skis wil float way better than the 3600s I believe.

But trust me, you WILL get stuck if you operate in deep snow much. It’s those multiple crusts that can really bite.....don’t ask how I learned that.

Go prepared to camp. When you get stuck bad, make camp FIRST, including a nice big fire. THEN work on getting unstuck. It may take a day or three.

Have fun!

MTV

JohnnyR
09-16-2021, 06:59 PM
I have a Burl's Magnum on an 8" tailwheel and another on my BBW wide fork. I don't have shimmy problems. My lock is long gone.

For various reasons we never installed our Airglas 4000 skis last season. Going to finally do so in a few weeks.

Now to deal with tail ski purchase question. Just got off the horn with Burl. He says the BBW ski is outselling the 8" Scott 10:1 for Skywagons. Additionally, he said the 8" Scott w/ski tends to exacerbate shimmy issues more than the BBW w/ski.

Burl also said tailwheel lock wasn't authorized with the 180/185 ski.

Given that clearance reportedly shouldn't be an issue with our 83" MT 3-blade and 850 mains, I'm thinking of leaving the BBW tailwheel on instead of switching back to our 8". We have a new(ish) stinger, bushings and mounts for the tailwheel spring, so shimmy hopefully won't be an issue either way.

Recommendations?
]
J

stewartb
09-16-2021, 10:37 PM
The Wide fork Magnum ski is easier to put on-take off once the permanent fitting is installed on the tailwheel head. I prefer it. I don’t know why Burl hasn’t changed the other skis to the same attach method.

Crash, Jr.
09-16-2021, 10:45 PM
Interesting that Burl is selling bunches of the Baby Bushwheel ski. All the feedback I've gotten from customers leads me to believe that the tail ski with the baby bushwheel tire doesn't steer very well due to the big rounded tire not cutting into the snow plus having more floatation so it's basically one big straight ski in the back. Maybe others that have run this combo can chime in. I've had several customers come back and say they really like the 3450 tailwheel with the 10" skinny tire with a ski.

Chances are good you'll have tailwheel shimmy with a ski if you're going to have shimmy at all since it increases the load on the shimmy damper in the tailwheel head.

All second hand stuff since I've never run a tail ski but just some things I've heard.

stewartb
09-16-2021, 10:52 PM
Steering on snow or hard surfaces? I haven’t used my 8” tailwheel setup for several years and never missed it. Skywagons don’t steer well in tight places with any tail ski. I’ll never go back to changing heads for summer-winter. The wide fork ski has been my choice since the day I bought it!

Charlie Longley
09-16-2021, 10:54 PM
Don’t miss working a big single on skis! That picture gives me the shakes!

I miss it……

aktango58
09-16-2021, 11:39 PM
Baby steps. If you are running in deep snow, put on a tail ski. Even if you have to weld a snow shovel onto a fork, you will want a tail ski on the 180.

Leave the pod, it will float the belly.

Crash, Jr.
09-17-2021, 12:31 AM
Steering on snow or hard surfaces?

Seems like mainly hard surface. The slick tread baby bushwheel wants to skate around from what I've heard. Of course in snow I'd imagine the ski itself does okay at steering.

stewartb
09-17-2021, 09:02 AM
I suspect the opinions you’ve heard are from guys on straight skis. The skis are probably a bigger problem than the tailwheel. On wheel skis the BBW does just fine. For hard surfaces with traction a smaller tailwheel steers better than the bigger ones. Having run a 14” XP for several years I find the wide fork to be a good all-around compromise. More so since Burl made the wide fork ski.

aktango58
09-17-2021, 10:40 AM
The LH4000 set I flew on a 180 was easy to control. Tight turns not easy unless you had traction on tires, on snow, no matter what we did we could only get so much turn out of them. In tight quarters on snow we would hold the brake for the outside ski, hit the switch to raise the skis and let the inside tire be exposed, then release the switch, (holding the brake on the outside ski would hold that plate in place to allow only the inside one to move first). Then make the turn holding the inside brake giving you drag, then stop and again toggle the hydraulics to put the plate back in place before you taxied.

You want a tail ski.

JohnnyR
09-17-2021, 11:23 AM
Thanks to everyone for input.
Two questions:

1) Flex line or hard line for hydraulic installs? Fly-Tek is recommending flex under the floor for ease of install. Pump gets mounted under floor behind station 108/baggage area, so multiple lines run out to the legs for quite a ways. I've always used hard line for brakes, etc. for weight savings, smaller size and durability. Maybe I'm outdated?
2) Likely cruise speed w/skis, 850's and BBW tail ski? We have a PPonk on the 180 and cruise @ about 125-130 kts TAS with 29's, BBW tailwheel, cargo pod & STOL kit. (22 squared @ 13.5gph @ 3000MSL)

stewartb
09-17-2021, 12:26 PM
I'll leave the speed answer to somebody who flies them. All I see is how they dangle when the skis are retracted. They have to be draggy. Probably better to cruise skis down. That's what I do with Fluidynes. I can tell an LH-equipped plane landing on our runway by the sound of the ski slapping down flat from the dangled position.

To the lines? Mine were always hard down the gear legs to a clamp fitting at the lower leg that held two bulkhead fittings and the ski lines attached there. They interfered with my Short Final jack so I removed them. When I go back on skis I'll probably go with flex lines and zip ties. They'll be removed with the skis.

aktango58
09-17-2021, 12:39 PM
Brakes, skis or anything like that need to have flex line to allow for the gear, ski or caliper movement. Hard lines will eventually crack.I saw one brake set up with hard lines that would only wear on one pad due to the line holding the caliper.

Speed- I think we were getting about 120 mph with 23 squared and skis down. Yes, once you launch you want to put the skis down with the LH, (and with the AWBs on the cub I lift them up)... Man it is hard to remember all the up/down/strait/fixed settings!:oops::-P

JohnnyR
09-17-2021, 05:54 PM
I should have been clearer. Im referring to hydraulic lines under the floor between station 108-mounted electro-hydraulic pump and fittings at top of gear legs

wireweinie
09-17-2021, 06:06 PM
Hard lines.

Web

stewartb
09-17-2021, 08:45 PM
Hard lines under the floor. Bulkhead fittings adjacent to the brake line. I like hard lines down the legs but like I said, they interfere with my jack so I removed them. It’ll be simple enough to make new ones. Here’s the clamp-on bulkhead fittings that terminated the hard lines near the bottom of the gear leg. The Fluidyne soft lines attached to these. I presume this was a Fluidyne part as they’re very nicely made.

All that said I’m in no position to criticize the use of soft lines under the floor. In my Cub when I retrofitted the new masters it wasn’t worth removing the floorboards so I snaked braided SS lines in between the masters and bulkhead fittings to the outside. It works perfectly. But the masters required a flex line being that they ride the rudder pedals. If they want to use flex lines I wouldn’t fight it.