Speed Mods

jstrahan

jstrahan

Filing Flight Plan
Joined
May 17, 2018
Messages
5
Display Name
Display name:
jstrahan
I am considering buying a Piper Archer and was wondering who does better speed mods, LoPresti or Knots2U. Although I am a long time pilot, I have never owned an aircraft before and would appreciate some advice. Thanks.

(the year of the Archer would be somewhere from 1975-1994)
 
I truly don't think it matters...as an owner of a very mod-loaded Piper...they hardly make any noticible improvement. As @Checkout_my_Six said, buying a faster plane is waaaaaay cheaper. The only mod on my Piper that I think makes a noticeable difference is the Powerflow exhaust. All the fairings, gap seals, wing tips, etc, don't change anything if you don't change the prop, and these Pipers need the lower prop for a decent climb so you really shouldn't change it.
 
Last edited:
I bought a Comanche with just about every LoPo mod on it. Instead of 155kts I get 165. Bought it that way, wouldn't spend the money if it were my own. Looks cool on the ramp though.
 
jstrahan said:
I got my commercial in a Mooney M20J in 1985. They seemed a bit cramped. I prefer Pipers.
Click to expand...

Piper Archer:
Cabin Height: 49”
Cabin Width: 42”
Baggage volume: 24 cft

Mooney J:
44.5” (lower roofline results in lower seating position)
43.5”
17 cft (doesn’t include hat rack, ~2cft, which is limited to 10 lbs).
 
tawood said:
I truly don't think it matters...as an owner of a very mod-loaded Piper...they hardly make any noticible improvement. As @Checkout_my_Six said, buying a faster plane is waaaaaay cheaper. The only mod on my Piper that I think makes a noticeable difference is the Powerflow exhaust. All the fairings, gap seals, wing tips, etc, don't change anything if you don't change the prop, and these Pipers need the lower prop for a decent climb so you really shouldn't change it.
Click to expand...


I'm glad you posted that. I was on the fence. I guess I'll just buy gas.
 
I guess I’ve been a bit nervous about Mooney’s, ever since that cult was started.
 
Chip Sylverne said:
I bought a Comanche with just about every LoPo mod on it. Instead of 155kts I get 165. Bought it that way, wouldn't spend the money if it were my own. Looks cool on the ramp though.
Click to expand...

Does it have the cowl also? I think that mod was something like $15k.
 
dans2992 said:
Does it have the cowl also? I think that mod was something like $15k.
Click to expand...

Yep. Only thing it doesn't have are the wing root fairings. Not the best pic, but you can see how much tighter the cowl is20170820_175946.jpg from this angle
 

Attachments

  • photo.JPG
    photo.JPG
    150.7 KB · Views: 77
kayoh190 said:
Wish they had folded the gear on the Dakota.
Click to expand...
Cirrius doesn't fold gear.....low pressure wheel paints and strut shrowds will make a difference.

BTW....I have FSDO "approved" plans for PA-32 (works for PA-28 too) low pressure wheel pants. $50 gets a copy.
 

Attachments

  • wheel pants 337 view.jpg
    wheel pants 337 view.jpg
    112.7 KB · Views: 64
Last edited:
The problem with speed mods and Cherokees is you are limited by the fixed pitch Propeller. Furthermore you are limited by the take-off performance the fixed pitch prop can provide, minimum static RPM and maximum engine RPM.

So basically you would be souping up a car that has ONLY 2nd gear. It’s only goingvto go as fast as the gear (prop) and engine RPM allow.

Speed mods on a Cherokee CAN buy you a bit more miles per gallon, but usually not much more speed unless you can change the prop pitch.

A Cherokee with ALL speed mods completed AND a speed prop is a Grumman Tiger or Cheetah.
 
K2U makes their own speed mods, as does LoPresti. However, LoPresti is far too proud of them. $1k a knot is the going rate. I had all K2U mods on my Archer which resulted in 130 knots true. Worth it for 5 knots? Not really.

Buy a TruTrack AP with the same money.
 
Checkout_my_Six said:
buy a faster plane....much cheaper speed mod. For thousands of dollars (AMUs) spent....I can't imagine getting more than 5-6 more knots.
Click to expand...

^^^ What he said. Speed mods are an absolute waste of money and time.

If you buy EVERY speed mod available, you MIGHT get 5 knots. Other factors like a worn prop or rigging are tangible speed improvers.
 
Oh....that reminds me. One of the best Cherokee speed mods is getting your flaps adjusted max up. Many (check the TCDS for your SN) will allow a negative 2 degrees up. That's worth 2-3 knots.
 
Checkout_my_Six said:
Oh....that reminds me. One of the best Cherokee speed mods is getting your flaps adjusted max up. Many (check the TCDS for your SN) will allow a negative 2 degrees up. That's worth 2-3 knots.
Click to expand...
I remember an article that said just getting it rigged is good for a couple of knots as well.
 
Get rid of the coffee can red strobe on the tail, reduce or eliminate antennas, clean up the little things, and that all helps a lot, those easy changes gained almost 5 mph. I added the Laminar Flow nose wheel fairing, and gained about 4 mph, Aileron and elevator gap seals helped with control at slow speed... Will be adding the Laminar Flow main wheel fairings next to gain some more...

For the flying I do, it is worth the cost.. Doing all the work myself helped with that cost. Being more efficient at a given speed is more important then just pure speed, but is fun to see 160 mph at 2500 ft full power.... not to bad for a little hot rod Cherokee 140
 
I had a Cherokee 180 with the O-360 and put on gap seals and wing tips. When I did that it wanted to take off on its own, well I saw very little in speed, but much more improvement in control. Then I bought the Commander 112 with the IO 360. More room/speed by 25 kts. Then when I painted black around the windows I gain another 10 kts on the ground. :)
 

Attachments

  • planeHanger.jpg
    planeHanger.jpg
    164.4 KB · Views: 77
  • IMG_2837.JPG
    IMG_2837.JPG
    160.1 KB · Views: 75
bgmac said:
I had a Cherokee 180 with the O-360 and put on gap seals and wing tips. When I did that it wanted to take off on its own, well I saw very little in speed, but much more improvement in control. Then I bought the Commander 112 with the IO 360. More room/speed by 25 kts. Then when I painted black around the windows I gain another 10 kts on the ground. :)
Click to expand...
I've never seen a Cherokee tied up like that...why have the front wheel off the ground? (I only do it for maintenance / pants removal).
 
tawood said:
I've never seen a Cherokee tied up like that...why have the front wheel off the ground? (I only do it for maintenance / pants removal).
Click to expand...

True, I was just finishing an annual and put the wheel and pants on. Thought it looked cool so I took a picture. I'm somewhat of a big guy and I can push down on the back of the plane and tie it down to an anchor in the concrete floor.
 
MBDiagMan said:
Which Piper offers the same speed per gallon as a Mooney? Pushing away from the dinner table will make the Mooney fit just fine.
Click to expand...

Thank you for proving my point. I don't much care about "speed per gallon". The plane should fit me, not me the plane. "I'm not a Marine. I believe in my comfort." (what movie?)
 
What movie what?

BTW, my wife and I both believe in comfort as well as control precision(I loathe the thought of going back to a cable and pulley aircraft,) speed, fuel efficiency, simplicity and reliability. That’s why we boutpght a Mooney.
 
MBDiagMan said:
What movie what?

BTW, my wife and I both believe in comfort as well as control precision(I loathe the thought of going back to a cable and pulley aircraft,) speed, fuel efficiency, simplicity and reliability. That’s why we boutpght a Mooney.
Click to expand...
The reference to a movie is from a line in The Green Berets, spoken by actor Jim Hutton. My only experience in a Mooney was about 20 hours getting a commercial in an M20J over 30 years ago. I didn't like them much. I felt they were more 'cramped' that other similar sized aircraft. "Simplicity"? I didn't see such. As for speed, fuel efficiency, and reliability, my experience was too limited for a definitive opinion as to those items. I also prefer an airplane that is more affordable to acquire since I am in the market to buy my first plane. Mooneys are simply too expensive. I've checked. BTW, my avatar is a picture of the airplane that my youngest daughter is getting her Private in, a 1977 Piper Warrior II.
 
Checkout_my_Six said:
Oh....that reminds me. One of the best Cherokee speed mods is getting your flaps adjusted max up. Many (check the TCDS for your SN) will allow a negative 2 degrees up. That's worth 2-3 knots.
Click to expand...
....it also increases the stall speed by a few, but you're landing with flaps so that brings it back down again. ;)
 
jstrahan said:
I am considering buying a Piper Archer and was wondering who does better speed mods, LoPresti or Knots2U. Although I am a long time pilot, I have never owned an aircraft before and would appreciate some advice. Thanks.

(the year of the Archer would be somewhere from 1975-1994)
Click to expand...

The best speed mod for an Archer is retractable landing gear. IE, an Arrow. Better yet, a Mooney or Bonanza... But of course, faster plane usually means higher purchase price. So...

The best "speed mod" you can get and still have it be an Archer is to get one of the newer models with the fully faired landing gear. The early ones could have wheel pants, but even if they did, they left the brakes hangin' out in the breeze, among other things. This changed around 1978 or 79, so you want one newer than that.

This is the kind you want:

archerpants-new.jpg

This is the original style - Note all of the uncovered stuff on the inside of the wheel and the much smaller pant:

archerpants-old.jpg


MBDiagMan said:
Which Piper offers the same speed per gallon as a Mooney? Pushing away from the dinner table will make the Mooney fit just fine.
Click to expand...

Bah. I'm 6'4" and over 300# and I fit in my Mooney better than most any other 4-seat single. "Mooneys are small" is an OWT, unless you're talking about the back seat of a short-body model. But I don't think any of us sit in the back, and my long-body is just fine in the back. The "small" impression can also come from the instrument panel being closer to you, but I much prefer it that way. I used to get a backache on instrument lessons in the Archer from having to lean forward to do stuff on the panel so often. Another place it comes from on the early models is the more-vertical windscreen and its position relative to you - It's in the same position as any other plane relative to the instrument panel, but as I mentioned, that's closer to you. But, I don't spend any time above the glareshield, nor does anyone else, so any space you may have had there is wasted anyway.
 
TigerGene said:
The problem with speed mods and Cherokees is you are limited by the fixed pitch Propeller. Furthermore you are limited by the take-off performance the fixed pitch prop can provide, minimum static RPM and maximum engine RPM.
Click to expand...

Constant-speed prop would help takeoff distance, climb rate and high-altitude performance, but not necessarily cruise speed. Through the 1972 model year, fixed-pitch prop was standard and constant-speed prop optional on both the Cherokee 235 and the Cherokee Six 260. On both, book cruise speeds were 2 mph slower with the constant-speed propeller.

Screen Shot 2018-05-26 at 9.17.54 PM.png

flyingcheesehead said:
The best "speed mod" you can get and still have it be an Archer is to get one of the newer models with the fully faired landing gear. The early ones could have wheel pants, but even if they did, they left the brakes hangin' out in the breeze, among other things. This changed around 1978 or 79, so you want one newer than that.
Click to expand...

The change to the bigger wheel and brake fairings was with the 1978 model year on all US-built fixed-gear PA-28s and PA-32s. They do help reduce drag, but they're a pain should you ever be inclined to inspect or service tires or brakes. :mad:

Oddly, PA-28s and PA-32s built under license by Embraer in Brazil were still built with the old-style fairings well into the 1980s. http://www.airliners.net/photo/Aeroclube-de-Eldorado-do-Sul/Embraer-EMB-712-Tupi/537223
 
Last edited:
You must log in or register to reply here.
Back
Top