PA-18 with C90 - Mods - When to Stop

[sdischer]

At some point, every project reaches the point of diminishing returns and that is what I am trying to evaluate and stop short of so I am asking for opinions here.

I have a very clean SC with a C90. STC's include the FA Dodge X-Brace, Cubcrafters gap seals, Micro Vortex generators, Clevelands, FA Dodge Safety Cables and I think that's it mostly.

Here's my question: I am considering extended gear like the Cubcrafters 3x3, AOSS or Acme suspension (if they get certified) and bushwheels but my concern is that I am putting lipstick on a pig at that point because it is still a C90 and so will I benefit much off airport with the improved suspension and better AOA even it is still only 90 HP. Any thoughts?

 

[mvivion]

If you’re doing much off airport work, the Bushwheels are great. I’d stop right about there.

MTV

 

[sdischer]

If you’re doing much off airport work, the Bushwheels are great. I’d stop right about there.

MTV

So add Bushwheels but not extended gear? Go all the way to 31's or just 29's? Thanks in advance.

 

[MZ18]

There’s been a few threads in the past asking the same question, most of the responses were to keep it light and simple. I’ve had my C90 PA-18 for a while now and I’d have to agree. I enjoy mine for what it is, sticking to mostly grass strips. It’s basically stock except for light weight battery, light weight starter and alt, and safety cables. If I ever want a more capable modified Super Cub I’ll build or buy one.

 

[1934A]

What is the current weight of your plane as it is?

 

[ag-pilot]

The 90 hp Cub I built up had light weight everything, then 3” extended gear,flaps,and a 74” prop. It is a little rocket ship as long as it’s not packing a hugh load and kept up with a whole group of us guys flying around on skis having a blast...or maybe it was blasting things. I did have to give the buddies flying it 10 gallons of gas to get them back with us as they were using all 90 hp all day and our 160s were loafing part of the day.

 

[KevinJ]

Shed the starter and put that weight towards a pair of 29” Airstreaks. A light weight prop and acmes sure wouldn’t hurt....It’s probably more important to see what you can subtract instead of add?

 

[sdischer]

What is the current weight of your plane as it is?

990 lbs

 

[sdischer]

Shed the starter and put that weight towards a pair of 29” Airstreaks. A light weight prop and acmes sure wouldn’t hurt....It’s probably more important to see what you can subtract instead of add?

tempting but so many years of propping my J3 and now electric start has spoiled me!

 

[MZ18]

Shed the starter and put that weight towards a pair of 29” Airstreaks. A light weight prop and acmes sure wouldn’t hurt....It’s probably more important to see what you can subtract instead of add?

Think I read somewhere on here that you’d need a field approval for airstreaks on PA-18-95, it didn’t make the STC list or something along those lines.

 

[1934A]

990# is plenty heavy for a C90... I'd be hesitant to add any extra weight if I were you. Sounds like you need a 775# PA-11!

 

[KevinJ]

Think I read somewhere on here that you’d need a field approval for airstreaks on PA-18-95, it didn’t make the STC list or something along those lines.

I guess Pierce would be the go to on that or use the catto stc. It allows for airstreaks I think.;-)Not really. I didn’t say that

 

[skywagon8a]

So add Bushwheels but not extended gear? Go all the way to 31's or just 29's? Thanks in advance.

What do you expect to get with the extended gear that the bushwheels will not provide? They both increase the relationship of the wings angle to the ground. Doing both seems excessive perhaps too much, particularly with a 90 hp Cub.

 

[sdischer]

What do you expect to get with the extended gear that the bushwheels will not provide? They both increase the relationship of the wings angle to the ground. Doing both seems excessive perhaps too much, particularly with a 90 hp Cub.

More clearance, more AOA, but again as other have said enough is enough and more may be too much.


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[Steve Pierce]

We operated a 90 hp Super Cub off gravel bars for many years. No flaps, 8.50s for a while but limitations on where you could go. 29" Airstreaks were great via Field Approval (I have a packet). The main reason I want extended gear is for prop clearance. No 82" props aproved for the C90 so that is an additional 5 lbs for not much gain in my opinion.

 

[skywagon8a]

More clearance, more AOA, but again as other have said enough is enough and more may be too much.

I can give you an example of too much angle of attack, though not in this case a Cub. I had an airplane which would fly "like" a Cub when very lightly loaded. It would easily get off the ground from a tail low attitude in as short as 2-300 feet. I would consistently let it fly off tail low in all loaded conditions. One day I flew it to Hampton NH where I filled it with freight which consisted of many boxes of WW2 British flying helmets. (Eventually sold them to Cole Palin at Rhinebeck, but that's another story.) Using my normal tail low let it fly off attitude, it would not accelerate to a high enough speed to fly. Oh Oh! Not a good idea to try to stop either! Pushed forward on the yoke raising the tail to a more level attitude, reduced the drag enough to accelerate and fly. Another lesson learned that day. Sometimes airplanes don't fly well heavy, under powered with a high angle of attack.

Your question of extended gear and/or bush tires reminded me of this incident.

The airplane was a Cessna T-50.

If you are considering an option of this type, go with the bushwheels and a stock landing gear. If you really "have to have" the extended gear you can do that easily later.

 

[Cub Special Ed]

Think about repitching the prop. C90 is a pullin machine. What you may constitute as lack of power could just be in pitch.
And i believe they make a 26" airstreak now. A couple of us runn aero classics around here.

 

[Chip D]

Here is a picture of my PA18-95. safety cables, 29" BWs, 71-43 prop. Just does not climb like a 150 SC.

 

[1934A]

View attachment 51811Here is a picture of my PA18-95. safety cables, 29" BWs, 71-43 prop. Just does not climb like a 150 SC.

What's it weigh? Electrical? Two fuel tanks? We need details!

 

[flyrite]

My mount obviously is not a super cub. But it is tremendously similar in what you have, in that it has a C-90, and an empty weight of just under 900 pounds. Get a good pulling Prop, Get plenty of seat time so that you fly the wing by feel in the lower end of the speed dial And you will go anywhere the higher horsepower guys go!
https://www.youtube.com/channel/UC3IUtbLBiBeIpTZRuF_QQog

 

[RaisedByWolves]

What's it weigh? Electrical? Two fuel tanks? We need details!

I don’t remember the weight but yes starter and alternator two 18 gal fuel tanks


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[Chip D]

starter, alternator, ADSB in/out, dual 18gal. tanks, extended baggage, safety cables, memory foam seats, Status transponder, Garmin radio, no toilet.

 

[Chip D]

Steve's gascolator, Steve high pressure master cylinders, Garmin 396, and foreflight. Tom have I forgot anything.

 

[Crash Jr.]

Remove anything that isn't absolutely necessary, add 29" Airstreaks, and add gas. If it's in the budget a 76/38 prop might be a worthwhile addition.

Honestly with how light the J3/PA11/18-95's are they don't need the extras that the heavier cubs do. Just learn to fly it and I think you'll be surprised how well it does. Extended gear is nice if you have a longer prop like 80" but really not needed for the shorter props on the small cubs. With 90hp dragging the airframe around the prime consideration is weight and anywhere you can save it. Even the stock bungees work fine just because you're not flopping down all that much weight.

 

[wireweinie]

Remove anything that isn't absolutely necessary

This is the 'prime directive' for all small aircraft.

Web

 

[RaisedByWolves]

Also the new aluminum lift struts are approved on pa-18. That will loose 12lbs


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[mvivion]

So add Bushwheels but not extended gear? Go all the way to 31's or just 29's? Thanks in advance.

I wouldn’t go to extended gear. If you can get the 29 inch Airstreak field approved, I’d go there in a heartbeat. If not, probably 29 inch BW. That alone will give all the prop clearance you need. And angle.

With an electric Cub, I’d swap the stock battery for an Odyssey or Earth X, preferably under seat with Atlee’s kit. Then, if electric stuff quits, replace with lightweight starter, alternator, etc. But only as stuff fails. Unless money is no problem. But those can reduce weight substantially.

MTV

 

[Dan Gervae]

Also the new aluminum lift struts are approved on pa-18. That will loose 12lbs


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Who is making those now? And how much??

 

[RaisedByWolves]

Who is making those now? And how much??

https://www.airframesalaska.com/Aluminum-Struts-s/2061.htm $3600. I'm sure they will go up from there

STC says 18 18s 18-105 125 135 150 l18c 19s I think that covers about all. The 18-90 i have here now is reg as an 18

 

[Chip D]

Yes, I would like to shed a 100 pounds or so but the plane is nicely set up. I just take longer to get to altitude verus the 150 hp. SC's. you can get into places but you really need to be conscious of getting back out. It all about flying the wing not the prop in a 90hp.