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Making a PA28 10 knots faster (and PA28 v. C172)

A search on PA28 speed mods turned up this šŸ˜†

EGHO-LFQF-KCLW, United Kingdom

Pilot_DAR wrote:

Less common aircraft place the owner at a greater risk that something goes wrong, and there is not enough economic incentive for ā€œthe marketā€ to produce repair parts. I think about this, as I own two type certified aircraft, of which only 38 were made in total, and only seven are flying. If I have a structural defect, Iā€™ll be on my own to work out an approved repair. The designer has passed away, and the type certificate holder has no capacity to provide any product support. Happily, when I bought the first of the two aircraft, a pleasing supply of brand new original parts came along, and most of the airframe could be repaired with standard materials if needed.

I’ve found in lots of experience with low volume stuff that the “luckily there is stash of parts that nobody wants” situation is almost always the case, and the Internet is a huge asset in finding it. Regardless, at 50 hrs per year per plane and with 1100 or 1800 total hours on the airframes, my planes need essentially no airframe parts and assuming I don’t crash them, that situation is never going to change in my lifetime.

There is also a practical maintenance related advantage in owning a plane that is likely the only one of its type that any A&P IA has ever seen, or will ever see. Coming back on topic, that also means that fairings might change here and there to provide a little extra speed.

Last Edited by Silvaire at 16 Jun 15:13

Aircraft which are operated as C of A certified will require certified parts for any required maintenance and repair. Yes, it may be possible to obtain used certified airframe parts depending upon resources and the permission to identify used parts as certified, but use parts, are just that – used. They probably have had a long service life of their own before being offered up for sale as used. If the airframe has been designed so well that structural fatigue and wear are not issues in long term maintainability – excellent! This is the case for some aircraft, just keep inspecting, and not finding any defects! Or, as some types, there are a multitude of simple repairs possible with common materials possible for the airframe, so if a defect is found, the repair is practical, and lost cost. An example of this is that most Cessna singles wing spars are made up of folded aluminum sheet, with common extruded angle riveted – though a lot of work, these could be made “in the field” and Cessna offers some structural repair data to point the repairer down this road. Piper low wing aircraft use special aluminum extruded “I” beams for spars, which cannot be made “in the field”. If you must replace a Piper spar, you’ll need a source of airworthy Piper origin parts.

The Blanik L-13 is an example of a good aircraft, which had a design problem become evident later in its service life, and generally was not economical to repair. Gomolzig in Germany designed and approved a repair kit, which I was shown during a factory visit there. It looked magnificent, though I agree that the cost to purchase and install might have been prohibitive. Less common aircraft place the owner at a greater risk that something goes wrong, and there is not enough economic incentive for “the market” to produce repair parts. I think about this, as I own two type certified aircraft, of which only 38 were made in total, and only seven are flying. If I have a structural defect, I’ll be on my own to work out an approved repair. The designer has passed away, and the type certificate holder has no capacity to provide any product support. Happily, when I bought the first of the two aircraft, a pleasing supply of brand new original parts came along, and most of the airframe could be repaired with standard materials if needed.

As said, choose the type which will satisfy your operational need, with a lesser dependence on going “really fast”. If “really fast” in the GA context is needed, Think of a newer very high performance single, or light turbine, and pay the cost. But no matter what you choose to purchase, or invest more into, assure yourself that there will be a longer term way for you to keep it operational at all. Manufacturers of legacy GA aircraft are showing themselves to be less concerned with economical support for those older aircraft.

Home runway, in central Ontario, Canada, Canada

People have been “abandoning” aircraft for as long as they’ve been building them. The real issue is how many there are in relation to demand, and how difficult it is to repair them (including regulatory constraints in any given area) and to find parts either NOS or from aircraft that have been “abandoned”. Neither of mine have had manufacturer parts support for many decades, long before there was an internet that makes everything so much easier, and unless they’re damaged in a pretty substantial way there is little doubt they’ll be flying long after I’m dead and gone.

Fix ’em and fly ’em

Last Edited by Silvaire at 15 Jun 16:03

Pilot_DAR wrote:

Increasing inspection and maintenance demands may devalue these older aircraft, and force them to simply be abandoned

…something I’m keenly aware of – our glider club has had to scrap one glider already (Blanik L13 due to the AD from the one that broke up in flight making the rest of them pretty much uneconomical to repair), and I’m having to scrap one glider (a Ka-8, needs a complete refurb due to the caurite glue issue). My powered aircraft was built in 1945. Although the cost of a fabric covered plane is you have pay to re-cover it every 15 years or so, the benefit is that it gets a really deep inspection and generally things are a bit easier to fix on a fabric plane with the fabric off than on a “modern” monocoque construction.

Andreas IOM

Another seminal posting from Pilot DAR, for which (from me, at least) sincere thanks.

But an issue that’s not been referred to is availability. I’ve heard plenty of stories about fancier planes that spend a lot of time on the ground waiting for parts. My Warrior is out there now, waiting for me. That’s how I like it! A few knots here or there is small fry compared with a plane that can’t fly at all for weeks on end….

So in the PA-28 world, we bathe in a cocoon of availability, even if the actual flights are sometimes grindingly slow. Oh, what’s that about a spar AD?

EGBW / KPRC, United Kingdom

It is wise to remember that the aircraft types being discussed are in large number, forty plus years old. These legacy aircraft have served much longer than the manufacturers intended, and that’s fine, as long as the maintenance continues appropriate to the condition of the aircraft. Maintenance demands will steadily increase, and parts supplies will decrease, and become more costly. Faster airplanes generally cost more than slower ones to operate and maintain. I do meet owners who are prepared to invest into an airplane sums exceeding what they paid for it, to get just what they want, in top condition. Generally what I see being done to these aircraft are not speed mods, the purchaser chose the characteristics they desired, they’re now focused on it’s condition.

Decades ago, it was possible to buy a GA aircraft in decent condition, fly it for a while, and sell it for a profit. If that’s still possible, it’s less likely now. Aircraft purchasers should choose their purchase with the mindset that they will buy the aircraft that they want for the role they envision, and as they use the plane, it will depreciate. Increasing inspection and maintenance demands may devalue these older aircraft, and force them to simply be abandoned. I have seen it happen, a 1967 Arrow, which had recently been airworthy, found to have a few coin sized corrosion spots in the very wrong places, could not be made airworthy, and was bought by the wrecker for $5000. Legalities aside, he could have flown it home for that, but the aircraft was beyond economical repair. That is fair, it had long ago paid back its investment in service. Just the last owner did not get that service, he got a couple of years of light use, and had to walk away from his investment. This is not the only example I have seen, but the one which touched close to home for me, I flew a 1967 Arrow for a year, and very much liked it – back when it was only 15 years old!

If the aircraft is to be bought to be flown and then written off, buy what you like, fly the fun out of it, and walk away when it becomes economical. If you hope to maintain your investment, choose very carefully what you buy, based upon its future maintainability.

Home runway, in central Ontario, Canada, Canada

alioth wrote:

The reasoning probably is: the ballache of buying a new plane and selling the old one, and the same plane that flies more efficiently wonā€™t have an increase in operating costs, whereas a faster plane is usually substantially more expensive to run (bigger, thirstier engine, maintenance and extra insurance cost of retractible gear, extra maintenance cost of CS propeller etc).

That and the simply fact that most people will bend over backwards to sit on their behinds rather than do the reasonable thing and just can’t be bothered.

Don’t get me wrong, I think the PA28 is a great airframe and it’s success over the years proves that. But it is what it is! To spend tens of thousands to get 5 knots out of an old airframe is simply madness.

And no, faster planes do not have to me more expensive, neither to buy nor to run.

Those who don’t want the expense of retracable gear and CS props should look at the Grummann’s. The AA5A Cheetah is considerably faster than a Warrior/Cherokee 140 with the same engine and prop, the AA5B Tiger runs close to 140 kts with the same engine and fixed prop, basically like an Arrow II but without the movable parts. They cost often less than comparable Archers or Warriors on the used market and have about the same operating cost.

Classic Mooneys with manual gear have close to the same operating costs (with the exception of the CS prop) but are often to be had very cheap on the market. You could sell a well kept PA28 and get a reasonably priced vintage Mooney for less money and spend the difference in making it up.

I am sure there are more comparable planes which will do 140-150 kts at similar costs than a PA28 but some of them may be exotic and that is why people shy away.

The popularity of the PA28 line (and the C172 line) always has been that they are simple planes which anyone can fly. But this comes at a price and that price is that they are not very fast. Either accept that or go for a plane which does what you need.

This whole thing is not only in PA28’s anyway. Speed mods sell like crazy with most airplanes and have often very few effect than looking great. But if I look at what I could get for my C Model Mooney to make it 10 kts faster, the price of this plus installation will very quickly be more than the airframe is worth. It’s simply silly to spend $50k to get 10 knots more (which is what could be done with a 201 style windscreen, new cowling and all the rest) when there are plenty 201’s or even M20K around in the used market who will do 160-180 kts for 30-50k to buy outright?

Yes, selling the plane is a real problem these days because real value is hardly ever paid. But it may still be the better way. Or, as we have been saying all along, buy the last plane first!

LSZH(work) LSZF (GA base), Switzerland

I think alioth is right, and is one of the reasons for the success of the Vans, great utility in a fixed gear/fixed pitch package. I was lucky that a previous owner invested in some speed mods which add around 5-10 knots – with zero additional associated maintenance cost.

…and 5-10 knots in a 105-120KTAS simple four seater is quite useful.

Oxford (EGTK), United Kingdom

The reasoning probably is: the ballache of buying a new plane and selling the old one, and the same plane that flies more efficiently won’t have an increase in operating costs, whereas a faster plane is usually substantially more expensive to run (bigger, thirstier engine, maintenance and extra insurance cost of retractible gear, extra maintenance cost of CS propeller etc).

Andreas IOM
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