Supercub Thrust Line

Diggler,

Do you and your dad weigh the same?

sj

delete

How much does the cruise speed increase? Has anyone done a real test with a GPS to determine the increased speed? It would be nice if someone could fly the same cub before the mod in four cardinal directions and average the ground speed and then compare to the same test after the mod. I have heard that the take off distance is reduced 30%. I don't want to sound like a non-believer, but has anyone done any real testing to determine if this is true. I don't believe it, but I really want to.

I am doing the mod to my airplane during the current rebuild, unfortunately I am also doing other mods like a 90" propeller and LEE so I will not know where my performance gains if any come from. I hope to be flying in a few weeks, it should be interesting.

I believe from what I have experienced it will be between 7-10 mph. I am calculating this from memory. I used gps and airspeed indications

Steve Pierce said:

The Husky mount is for a Dynafocal mount O-360 and is a little longer. It doesn't swing like a SC. I don't believe a Husky mount will bolt up to a Super Cub.

Click to expand...

I've got a conical one off an 87 model. maybe I'll check it.

Wow! 7-10 MPH!

That would be awsome! Now I can put the slats on with the zero thrust line mod and keep my current cruise speed.

Call Mark. If I am not mistaken they flew the plane before and after on a four point grid and came up with 7-10 miles an hour increase.

We had the parts shipped up and were ready to install them in two AC for the Valdez show. Up until two days before the STC was issued the FAA had indicated it should be no problem for the parts to be installed at the repair station in Big Lake or by the Company--ThrustLine Products of Alaska--with an IA sign off. Now the FAA is saying these parts cannot be installed without a PMA which we are hoping to receive. This is the short version. End result is we have parts-an issued STC--and a delay to get them installed. The parts can be used for Exp. To answer the pricing question. The price will be $1800 for the STC paperwork and kit. The kit by itself will be $1750. STC and kit can be returned for a complete refund if not satisfied. We are trying as hard as we can to get this STC installed so that some numbers can be posted for you to determine if this is something you might be interested in. About the cruise increase---Actual test flight data showed 4.5 and 5 percent increase on the 160 cub and 8 percent on the 180 Penn Yan cub.

If you have any questions please feel free to email me. If you need a reply over the phone include your info. I am to busy to take these phone calls as they come in but I have been returning calls as soon as possible. Thanks for the understanding during our start up. Sorry for the delay.

E-mail Address(es):
akcub@mtaonline.net

Mark

Michael Tracy said:

I have a question. If a Husky has a zero degree thrust line can I use a husky engine mount on an experimental cub project? Is the firewall bolt pattern the same?
Mike

Click to expand...

Bolt pattern is quite a bit wider. (about 8"). Wouldn't be worth it anyway. for the price of a husky mount, you could probably buy the STC or just modify a cub mount to give you the same results. (experimentally)

AkPA/18 said:

We had the parts shipped up and were ready to install them in two AC for the Valdez show. Up until two days before the STC was issued the FAA had indicated it should be no problem for the parts to be installed at the repair station in Big Lake or by the Company--ThrustLine Products of Alaska--with an IA sign off. Now the FAA is saying these parts cannot be installed without a PMA which we are hoping to receive. This is the short version. End result is we have parts-an issued STC--and a delay to get them installed.

E-mail Address(es):
akcub@mtaonline.net

Mark

Click to expand...

Do you own one of those aircraft? If so, why can't you install them under the "owner produced parts" rule? They are your parts, your aircraft, your STC and your design. FAA-PMA is for resale of parts.

S2D said:

Michael Tracy said:

I have a question. If a Husky has a zero degree thrust line can I use a husky engine mount on an experimental cub project? Is the firewall bolt pattern the same?
Mike

Click to expand...

Bolt pattern is quite a bit wider. (about 8"). Wouldn't be worth it anyway. for the price of a husky mount, you could probably buy the STC or just modify a cub mount to give you the same results. (experimentally)

Click to expand...

It was just an idea. If I choose to use a zero degree thrust line I would rather have a mount made that way to start. If there isn't one available I may make one. Thanks for the information on the husky.
mike

If Piper decided to sacrifice performance and flight characteristics simply to improve visibility, then I would like to modify my cub to correct the thrust-line. My preference would be a engine mount that is re-designed to accomplish the new geometry. I'm sure the lugs are of sound design etc... I just don't feel comfortable bolting spacers or lugs in that area. If an engine-mount mod becomes available I will be writing a check.

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Very informative Dig.

Just had the mod installed on my Penn Yan conversion. The replacement parts are much sturdier than what they replaced. $1800 for STC and parts and about 3 hours for installation. The plane flies much different. I am about 6'1" and I couldn't see over the cowling when taxiing (31' Airstreaks and 3" extended gear). I don't have any good objective data yet. My quick initial impressions based on very little flight time were 100mph, feels cleaner ( things happen faster, for example when you put the nose down after a climb you get to full speed faster), More thrust at low RPM settings(including taxiing). I will try to fly it more and get some more objective data soon, for now, get out the salt shaker when you read my opinions on it!

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I have no doubt that this modification is a good one, but I also agree that a change of this nature should be acomplished by alteration of the motor mount. I believe it would be safer, sturdier, and accomplish the same thing in a better way.
My other concern is with the price. A set of stock pa18 lugs is less than $50. ea. or less than $200. a set. I know that development, engineering, and other costs with the FAA had to be eccessive. But $1800. for the set,
$1750. w/o STC, seems pretty high to me. If Cubcrafters or some other lower 48 state cub co. were to be offering these parts for this price, I don't think I'd be the only one mentioning this. Then again, its just my opinion. And as we all know, we all have one of those!
Rich

thrustline

Propeye. I'm glad more people don't have your opinion. Or there would be a lot less people willing to invest 110K to bring you a superior product complete with a STC. If you know of a safer, sturdier or a better way, just put up your 100k and show us how to do it. Jerry. :-?

Can you imagine the testing that had to go into this to get it approved by the FAA? Manufacturing and changing the design of a part that holds the engine on. Changing the angle of the engine and proving that there are no ill effects in every flight regime. My hats off to Mark and everyone involved who obviously sacrifised there time and exuberant cost to improve the flight characteristics of the planes we all truely love. How much does Cub Crafters get for a bunch of little pieces of aluminum that glue to the leading edge of your wing? From all the Super Cubs I have seen I would bet the cost return is far greater on them than the thrustline line modification.

I'm with you guys, $1800 seems fair considering the engineering and testing work involved.

One small note however, Cub Crafters doesn't make and didn't engineer the little pieces of aluminum, these guys did:
http://www.microaero.com

-->Aaron

Rookie,

Actually, Cubcrafters use the Boundry Layer Research VG's which are different than the Micro VG's. They work similarly, but have a strake in back instead of the vg's under the stab. BLR may be owned by CC, I can't remember.

sj

Oh.

I put the Micro VGs on my airplane. Notice who's airplane is pictured on their home page?

Like 'em!

-->Aaron

stc's

$3000 for a Bore prop, $3500 big tires,$3000 for bigger tanks.
$1800 to much for any good product. Get a life!

I've often felt that flying a SC was more about getting on and off the ground than going from point A to point B. The mods Wayne points out address this aspect as does the exhaust mods, VGs, light weight starters, batteries etc. The only mods that do not address this, that readily come to mind, are the larger tanks and fancy seats. Yes, there are others.

As to the price, the economies of scale don't work real well with airplanes. Ford built 1,000,000 Mustangs in 1964 and many more since then. If the after market makes a performance mod for the mustang, there is obviously a larger pool, of potiential buyers, to draw out of. There were about 10,000 SCs built and I don't know how many are still flying. Lets say an after market mustang market produces a mod and maybe the manufacturer uses 10% of owners, as a number of buyers. This number may produce millions of buyers out of the mustang pool. Use the same number for the SC market that number may be in the hundreds. I applaud those that take the know how, risk, money, time and balls it takes to bring an idea from conception to stc and market. These folks keep improving our planes and keep them flying. I hope they do well and prosper.pak

I did some touch and gos at Lake Hood strip the other day. It really got some attention. The tower was very impressed to say the least. Pilots were asking about what the airplane had in it. All this discussion was on tower frequency. The plane seems to want to fly faster than my reaction time.
A few comments about Mark and Fred who installed this. They were outstanding at thier job. The doors actually fit better after they were done and all the contols (ie. lean, carb heat etc.) work as good or better than when I brought it in. They were also fun to be around.
As far as the price, I run a business and I understand overhead. He is not going to rich from this. I am just happy he put all the effort in so that I may enjoy it. General Aviation needs more people who are happy to support progress. This is progress. I will also support the next guy who does something this good for cubs (God willing). I love this lifestyle!

Thrustline

GEntlemen,
Thanks for all of your interesting dialogue one this subject. Although, dialogue such "Get a life!" and "put up your $100K and show us what you've got" hardly describes dialogue by my definition. To the two of you who made these remarks; Please forgive me , I had no idea I offended you this much.
Mark and I have had several PM's about the mod which I enjoyed and appreciated without any of this apparent resentment. He has also explained some things to me of which I was previously unaware. Had I heard these facts presented or discussed in an open and fair manner, I might have reacted differently.
Some of you have been within a loop of information on this mod which I and many others were unaware of. Maybe a good representation of the facts, amount of development and engineering involved, and the expenses would go a long way in conviencing myself and others that this product and stc is worth this kind of investment.
However, it has been my experience on this site, that if certain cub developers or manufacturers produce or offer a part or product for a certain price, it is slammed for being unfairly high priced. How is this any different then any other offering on this site or any other?
I expressed an opinion based on the limited amount of information which had been provided, and about which no discussion had occured. I have though and believed that we were all reasonable and fair people and I continue to believe that.
Stolmaster and Jerry Burr,
Forgive me for offending you in such a way as to ellicit the type of comments which were made. "Get a life!", and "put up..." hardly seems necessary from two individuals whom I have in the past admired for their knowledge, intelligence, and helpful contributions about supercubs.
Perhaps, if we spent more time sharing real information, and less time critizising others from our prejudicial perspectives, we'd get along better and make the world a better place.
To everyone on this fine site, please accept my apology for any offense I have given, because they were never intended. It concerns me that any of our discussions about supercubs should be construed as "unfriendly" by any person who would happen upon them.
Thank you all for your information and participation. My apologies for this convoluted explaination. Hope we can all still be friends!
Thanks,
Rich

Hey Popeye, I saw the way Jerry Burr ripped you for voicing your opinions and preferences on this mod. I can respect Jerry's opinions but I don't understand the need to "blow" when someone differs. In my opinion the mod should be done with the engine mount. Go ahead and vent Jerry, you overestimate my concern.

I, like everyone else want to spend as little as possible on aircraft mods, but this is a free market. Free enterprise is what makes this country so great!

Mark stepped up to the plate and took a risk, he might loose his ass or he might prosper, this is a great country. Mark owns the STC and design and he has the right to ask what ever he wants for it, just like we have the right to buy it or not.

I for one hope Mark is prosperous and hope that others will follow in his footsteps. Thats my two cents.

One other thing regarding the lug versus mount conversation. I am a licensed professional mechanical engineer and I do not see anything wrong with Marks design. In an ideal world, having a new mount with the new geometry would be ideal, but it would take a lot longer to install. If I was developing this STC I would do it the same way as Mark knowing what I know about it. Agin, my two cents. Lets stop bitching and lets here about the performance gains if any. If you can takeoff 30% shorter with this mod as claimed it should be worth $10,000+ in my opinion. I don't really think you will be able to take off 30% shorter, but lets here what people are experiencing. Can you get off shorter? How shorter? How much faster?

I was cleared to take-off at Hood yesterday when Ground Loop was doing his touch and goes. (I was in the Cessna that said I'd delay until you cleared). Indeed the tower and everybody out there was impressed. The tower asked if that was a maximum performance take-off. Groud Loop said "yes, and I'll stop doing it." The controller asked him to do some more so they could watch. I'm telling you, folks, the controllers at Hood see lots of Cubs take-off. This was different. What did the controller estimate? 20 feet of ground roll? The wind was a LH 40* crosswind at 8. 20 foot ground roll. Impressive mod, and worth every penny. I hope it works on a 12.
SB