PA-32R Speed Mods

[jmpoplin]

I am interested in getting some speed mods for a '83 Saratoga SP and wondering if anyone had experience good/bad with either Lo Presti or Knots 2 U? Seems the Lo Presti ones are more expensive but wondering if better quality?

So my question isn't should I get mods, it's which one to go with?

Thanks,
Jeff

 

[Norman]

One of our customers put a LoPresti cowling on his Lance. The only thing he has to show for it is a lighter wallet. No speed increase, and it's a bear to remove and reinstall at oil change time.

 

[Sam D]

One of our customers put a LoPresti cowling on his Lance. The only thing he has to show for it is a lighter wallet. No speed increase, and it's a bear to remove and reinstall at oil change time.

Prior to my buying in to our Lance, a number of mods were done. The LoPresti cowling was one mod we didn't do. We did do the gap seals and wing tips and I believe something with the landing gear. We plan for 200 knots cruise.




Just kidding. 155 kts at 8500'.

 

[dans2992]

One of our customers put a LoPresti cowling on his Lance. The only thing he has to show for it is a lighter wallet. No speed increase, and it's a bear to remove and reinstall at oil change time.

I'd demand my money back from LoPresti. Seriously.

With well documented "before" and "after" testing, LoPresti should guarantee X knots speed increase.

 

[mondtster]

One of our customers put a LoPresti cowling on his Lance. The only thing he has to show for it is a lighter wallet. No speed increase, and it's a bear to remove and reinstall at oil change time.

I have experience with an Arrow and a J model Mooney with LoPresti cowls on them. Same thing, no speed increase and a $15k or so bill.

My experience with maintenance on those two planes is the opposite however. The LoPresti cowls I've dealt with are the best fitting and easiest cowls to remove and reinstall. From a mechanic's standpoint I like them.

 

[dans2992]

How does LoPresti stay in business?

 

[N747JB]

Dang, you got me!! I was thinking 200 MPH, down hill with a tailwind, maybe!!
I'm a little skeptical about speed mods, it's usually a lot of $$$ per knot! Adding 5 knots to the average single on the average 200 mile trip is not much difference! Adding 10-20 knots on the same fuel burn is significant, but I don't think those mods are available!

Prior to my buying in to our Lance, a number of mods were done. The LoPresti cowling was one mod we didn't do. We did do the gap seals and wing tips and I believe something with the landing gear. We plan for 200 knots cruise.




Just kidding. 155 kts at 8500'.

 

[James331]

They are for people who are more interested in being ably to say they spent 15k on a cowl than anything to do with speed.

You want a noticeable speed mod for your piper. Put a bigger engine in it, plan for better winds, or buy a faster plane.

 

[JHW]

They are for people who are more interested in being ably to say they spent 15k on a cowl than anything to do with speed.

You want a noticeable speed mod for your piper. Put a bigger engine in it, plan for better winds, or buy a faster plane.

maybe it won't help the speed, but on the other hand it will cook the engine

 

[Jay Honeck]

I had every Lopresti speed mod on my Piper Pathfinder. They cost $20K, and added about 9 knots. Dumb.

I never would have paid for them, but they were already on the plane. It was kinda fun to outrun Arrows and early Mooneys, but I had to burn 14 GPH to do it.

 

[Neal Howard]

PA32 (or PA28 for that matter) biggest source of drag is the wing itself and not much you can do about that except trade for a different model of airplane.

 

[Checkout_my_Six]

get your flaps adjusted to the furthest allowable up stop.....-2 degrees (oh and bring the ailerons up even with the flaps). That'll get you an easy 2-3 kts...also, make sure your rudder trim is set correctly.

Other than that....upgrade to a PC-12.

 

[Bill]

A-36?

 

[James331]

Or just enjoy the time flying.

I fly a PC12 for work, my personal plane is a 120kt plane.

For the money I could have purchased a white lightning or a lancair, but that's not what it's about for me, enjoyment per hour > MPH.

 

[Ted]

Speed mods are funny things. I've been putting a lot of effort into extracting extra knots out of the 310 using relatively basic options. For me, an extra 1 kt in cruise subtracts 10 minutes off of my long Cloud Nine trips. 10 minutes doesn't sound like a lot, but 6 kts subtracts an hour. Now we're talking.

One thing I've noticed is that without an Aspen or G500, it is very hard to determine speed increases. The old steam ASI makes it difficult at best to determine when you've increased 1 kt indicated.

Then there's other drag factors. The plane itself is the biggest drag. So, ailerons and flaps are important. Some may have tricks. On the 310, drooping the ailerons a hair (basically putting it within the bottom of the limits) gained 3 MPH TAS for economy cruise, but 7 MPH TAS for power cruise.

Weight and CG - can you put your plane on a diet? How about keeping CG towards the aft limit? When the Aspen got installed the 310 lost 65 lbs in the nose. I didn't observe a speed improvement, but remember what I said above regarding analog ASI. I'm planning on removing the O2 bottle in the nose at this annual (which I never use since I have a portable). That's another 50 lbs or so.

Check your engine baffles. Fixing them on the Aztec gained me 5 MPH IAS. On the 310 they weren't bad, but extra attention to detail on them seems to have gained another 2-3 MPH or so. A hot engine produces less power, so that drag reduction could be offset by baffling that isn't optimal.

What about your exterior lighting? Belly strobes and beacons are often horribly draggy. Better options exist.

All in all, when I started flying the plane, 2500 RPM/24" ROP was about 188 KTAS at 6k. Now, 2500 RPM/24" LOP (so less power) does 190-194 at 6k. I have more changes left to do and I think I can hit 200, and none of these are actually "speed mods" so much as attention to detail.

If you want to make the plane faster, first focus on the plane itself. Then consider upgrades.

 

[Checkout_my_Six]

down ailerons?

 

[Ted]

down ailerons?

Yep. Worked on the 310. I need to do some more calculations on why, but the 310 responds well to an aft CG and I've noticed about 1-2 degrees more nose down in cruise with that change. So I think what happens is the drooped ailerons move the center of pressure on the wing forward. The tail responds with some nose down trim for level flight. That's the theory, anyway.

Not all 310s respond well to this, but N488SP sure did.

 

[Checkout_my_Six]

I'm thinking the PA-32 maybe different.....mine was.

maybe the 310 is also faster with the flaps down....?

 

[Ted]

I'm thinking the PA-32 maybe different.....mine was.

maybe the 310 is also faster with the flaps down....?

I'd expect every plane to be different, that's why I said some might know tricks for the plane. Like you.

The flaps add drag. They're also split flaps. Nothing to be gained there.

 

[AdamZ]

I had every Lopresti speed mod on my Piper Pathfinder. They cost $20K, and added about 9 knots. Dumb.

I never would have paid for them, but they were already on the plane. It was kinda fun to outrun Arrows and early Mooneys, but I had to burn 14 GPH to do it.

You forgot the speed mod that got you the biggest increase............buying an RV

 

[Jay Honeck]

You forgot the speed mod that got you the biggest increase............buying an RV

Yup. In the end, if you want to go fast(er), the only solution is to sell the Cherokee. It's a nice, comfy plane, but its just never gonna be sleek, no matter how many legal speed mods you add.

Now, find a guy with some bondo skills...that's another story. But then you're experimental.