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Supercub Thrust Line

I recently installed the thrustline kit on my Dads PA-18 for him. I would not have believed how much better it flew if I had not flown it myself. It took a average to below average flying cub and turned it into a way above average flying cub. The quality of the product was top notch, installation was easy. Mark was a hugh help on the Tech end of things for measuring up the cub before hand and after as well as on wing rigging. It is a rarity in this day in age to find a guy with his kind of integrity that will stand by his product to the end. If you are not happy with it he wants to give you your money back. He even did a couple follow calls to make sure we were still happy with ours. My hats off to you Mark.
Shawn
 
Ditto what ak2711c says. My dealings with Mark on his Thrustline kit stand out as one of my best experiences with a vendor.
 
TL

Last week we put the TL mod on a friends 150 cub with a wood prop. Although I did not fly it "before" I did fly it after and thought it did real good. I could touch the tail with the 26" goodyears about 18" off and drive it right down the runway with a touch of power. The more I fly this mod the more I am seeing all the little gains we are seeing like less back pressure in a turn, Way better climb, way more control on landing and way less power "fuel" to fly around at 70 mph.[2100 before-1900 after].
We were wondering if we would see the performance gains with the woodie on the top side but the owner says he picked up 4-6 at 2500.
Way to go Mark!!!

Dave
 
AGpilot. In February, your suggested that you would be taking the VG's off to test the TL then putting them back on for comparative numbers. Did that happen, and what were the results ??
Mark, My son and I have a stock "89 cub with 150hp. Would we see gains similar to those seen by the 160 and 180 hp cubs ??
 
TL mod

T-28, Yes I went on and off with the VGs several times. Then I glued them on for good. My results are:

Power Off stall Before TL mod and VGs I would get a good break and it would try to come around if the ball was not centered or if you worked the rudders much.

Then I put the TL mod on by itself.

Takeoff and landing was shorter with the landings more stable and controlable. It took less back pressure to hold it in a level tight turn and climb was at least 200 fpm better.

Then I put the VGs on the wings only and the only thing that seemed to help was the stall was a touch less severe.

When I put the tail VGs on I could horse it off touch sooner [maybe] did not notice any difference in roll rate but the elevator was quite a bit more effective and the BIG difference and the reason I left the VGs on was that I can now do a power off stall with just me in the plane, hold the stick back to the stop and all I get is about 350-450 fpm sink. I can even walk the rudder quite a bit without any sign of it wanting to tuck its nose or drop a wing.

I was hoping to see a gain in roll rate with the VGs and maybe a bit lower stall speed but if its there I or my GPS can't detect it.

Dave
 
All I know is I flew next to a TL cub with the same engine, prop and weight as my cub and I have never been whooped so bad in a take off and climb contest in my life. :oops:
 
TL mod

Yeah Kase and it didn't have anything to do with the pilot because when we switched planes You wooped me!
Dave
 
Affimative someday. Right now extra fuel cost and my wifes new car are cutting into my airplane improvement fund.
 
I installed the Trustline mod on Steve Edwards 135hp Super Cub at New Hostein. He flew a GPS course and immediately realized a speed increase. I flew it and never had to touch the trim from take-off to cruise flight to a full flap landing. When i got on the ground Steve asked me about the trim. He had the same experience.
 
I now can honestly say I like the Thrustline mod.

We put it on my 150 cub on floats. I fly survey for the state, spending long hours low level in cruise.

Due to the constant heavy loads, I don't do much super slow work, but I immedatly picked up 6 or 7 miles an hour in speed.

It has taken a while to get the attitudes correct, but will say that I found myself climbing all the time. Once I got it figured out, I realized that the plane was actually performing better in climb, so was more sensitive to pitch attitude.

Takeoffs were better also. I figure I save myself between 20% and 30% of the time getting from plow to on step, a great place to save time.

Once I get speed and jump out of the water, there is almot no hesitation to gain speed. I used to fly ground effect for a few hundred feet to build speed; now I come out, think speed and climb out at 60mph.

We played hell getting it on the plane, so if again, Mark can come and do it himself, thankyou very much. Why should we get all of the fun? Gotta love a "stock cub" that has been ownerized by previous owners!!! :bad-words: :bad-words:

Product support was better than excellent. Mark made himself available for questions, offered tips, was fantastic to deal with when delays had the kit on my bench for two months, and he kept reminding me to tighten the nuts after some hours.

Thanks Mark, I look forward to you new and great mods you come up with.
 
Steve P echoed my experiences on the TL mod and trim. I noticed that when pulling the first notch of flaps the nose doesn't balloon up like previously.
Lot's of subtle little improvements with the mod. When hauling the cub off with flaps in a short field takeoff the tendency to sink is gone, the nose stays up and you are climbing right away and the cub does get off shorter and climbs better. On landing slow, before it took a noticable power application to arrest the sink rate, now just a touch of power is needed.

Hard to define all the improvements but the cub just feels lighter with power.

Steve
Dodge City America
 
I havn't noticed the need to trim more. I did notice that when pulling flaps on approach, the need to retrim for different flap settings was noticably less.

One thing I didn't test before the TL that others may have is that now with about 1800 rpm on the tach and full flaps the airplane will chug along very nose high and indicating about 10 mph. I am guessing before the mod the attitude would have been more flat.
 
Thrust line mod for PA-18

I decided to give the thrust line mod a try on one of my cubs.
With cash in my pocket I meet Mark the owner of Thrust line At Big Lake. Mark spent a hour wit with a digital level looking over my cub. He told me that he did not think this particular cub would benefit enough to make it worth the money to buy his mod. This cub has been repaired many times and is no longer straight. It preforms OK but is the only cub I have ever owned that did not like wheel landings.

Mark acutely turned down my money and did not sell me his Trust line Mod. He and another A & P spent 2 hours fine tuning the rigging of my cub with digital levels. I was amazed THe cub now wheel lands like my other cubs and is 4 miles per hour faster at 2450 RPM. All this and I was only out $100. for the 2 hours shop time for the rigging.

I am impressed with the results of what Mark did for my cub and plan on buying the thrust line mod for my other cub that I am rebuilding with a New fuselage and all new parts.


The point of this Posting is let people know that Mark knows his stuff and is honest enough to turn down mony if he does not think his mod will help your cub.


Jerry Jacques
 
Jerry, who's new fuselage frame did you buy?

You oughtta measure it, too.

Good for Mark, telling it like it is!
 
Mark has helped Me many times on the new Light Weight cub I am building to compete at Valdez next year.The word honest is Marks moto,unlike some people.Mike O.
 
No doubt about it, Mark is one helluva guy. I was lucky enough to meet him at Minam Lodge in Or. last month. What better way to stand behind your product than to tell you it wont help your plane. Name one other performance mod company that does that.

Most of you guys have heard about Lonnie from the "big rocks long props" video. You may not see him post much on this forum, but I heard he thought the T/L mod was the most noticeable improvement to his cub other than the Borer prop. When it works, it works great.

Jason
N3673T
 
The new fuselage I have is from Airframes INC in Big Lake. It arrived in April the workmanship looks good. I will start that project next month
and plan on installing the thrust line mod in that one. Mark tells me that with every thing straight the mod will work.
Jerry
 
Thanks for the kind words guys albeit a little on the embarrassing side :oops:

Just to clarify Jerry's post. He came in about two months ago to Wasilla to get measured for the TL. His wings were visually out of rig with about a degree and a hlf too much twist and a bit too much dihedral. I asked him how it flew and he said it would not wheel land. I told him in theory we should be able to fix it. Did not have time to deal with it then as he was working a Beaver out west. He came in a week or so ago and we measured and rigged it to the book. Theory worked as he landed with a pretty big grin.

For the folks at Minam flyin that heard me explain the rigging for a cub---I apologize that I am not much of a teacher. As I was explaining how simple cub rigging is, I noticed just a bunch of blank faces. I really am terrible trying to explain stuff to a group! But the above cub of Jerry's is a good example of the type of rigging we have been seeing now that we are putting the level on these cubs. Any more dihedral or twist than book--you will not get the performance you should be getting.

In that little discussion at Minam I made the statement that somewhere on the strip there was a piper that was probably so far out of rig it would look deformed. The next morning a piper parked in front (50 yards away) of where Ag pilot-Kase- Wayne and myself were sitting. Huge amount of visible wash. I think we all saw it. I mean huge! I asked the owner if I could put the level to it and he said sure. It was a 5 degree twist between the wing root to the end of the aileron bay. His comment was just that it was always like that. Sure hope he re-rigs it and lets me know the result. Just some food for thought for those of you who assume your AC is rigged properly as we are finding a fair amount of them that are not.

http://sparky.supercub.org/photopost/showphoto.php?photo=5360&size=big&cat
Above link shows cubs with different visable wing twists--cool photo

A bit of a disclaimer here. I always work with an IA or repair station as I do not have any of the pedigrees---Just want folks to know that if you are taking any of my advice.

Mark
 
The thrustline kit that I won at the NH Fly In is now installed in 8439Y in Millinocket. Just got offthe phone with Jeff and he says the difference is huge on the landing and takeoff. The indicated speed in cruise was up to 105 mph. Will get my hands on her next week as work gets in the way along with WAD preparations.
Thanks Mark
John
 
Thrustline

This is a first post for me because I am not into typing. I promised Mark I would tell what I thought about the thrustline. I feel any company with this much integrity deserves an honest feedback.
Just before I was to install the TL I took the 160 HP Borer prop 31 BW 3" extended gear cub out for tests. About 10 minutes in the air I lost all all oil pressure (not good). To make a long story short, I landed safely but didn't have much time to do any tests. During rebuild to save time and money, I installed the TL. Since most all my flying is off airport, I will tell you what I think in that area.

1. Better steeper climb out.
2. In cruise, feels like the tail is a little higher. I think I have around 5
mph faster cruise.
3. Landings took a little getting used to but now are much slower,
especially with weight. It's a little harder to see touchdown over the
nose just before landing in real slow landings. I got better at just
flipping the tail up to take a look and then landing tail low wheel
landings, once on roll-out you can see great. Who cares if you can't
see while taxing. I couldn't see before the TL anyway.
4. Take off on rough stuff and popping flaps a little too soon, it doesn't
sink back like it would before but just keeps climbing.
5. Most noticeable, slow landings in a turn are much more stable.

Sorry, there are no hard numbers like miles per hour but in my opinion the thrustline is an edge of the envelope mod where you don't look at the numbers anyway. I think this is a great company that really cares and I highly recommend the thrustline mod. The parts are superior and I really like the one piece lower cowl channels that I still need to install. My thanks to Mark!
 
I also have the Thrustline, As far as not seeing over the nose it's something a person gets use to, I've been flying with the thrustline for about 7 months, I would never take it off. Some people don't like it because it changes the look. I had new cowling doors made to match everything up and to the untrained eye you could never tell. The performance is very nice. Getting back to not being able to see over the nose=== Fly a pitts! You diffently can't see over the nose, but after awhile you get use to it.
 
Looking for U-bracket engine mount take-offs from Thrustline folks. If you have a set you would like to part with let me know. For my experimental.
 
Erik said:
If going from negative TL to zero TL is good, could going to positive TL be even better for STOL? (let's discount the visibility issue, because that's a given)

Yes, it is.

CV22_main_750x250_46558.jpg
 
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