NMUSAF Piper PA-48E Enforcer for sale

[kalamazookid]

I'm wondering if "not airworthy or suitable for flight purposes" means that one of the conditions of sale/trade is it isn't flown.

[Snake45]

I'm wondering if "not airworthy or suitable for flight purposes" means that one of the conditions of sale/trade is it isn't flown.

I sure hope not. Would be a shame to NOT see it in the air again. And I'll bet it would find plenty of paying customers for rides.

[Lon Moer]

Technically its "for trade". What they mean is that when they accept a bid the money will be put in an escrow account, when the museum locates something they want then that money will be used.

There are also no restrictions on the sale as to flying the airplane.
As it was never actually accepted to the USAF, it is a civilian registered aircraft.

[Zac Yates]

Don't think they had one back then, but I do remember some planes being set aside in a fenced in enclosure for the museum(?).

Mac

They had it stored outside for a while IIRC, but it has since been restored and looks great! Wikipedia says it's just N481PE (subject of this thread) and N482PE (restored and on display at Edwards since 2014), the two true Enforcers, that survived. Of the earlier version the dual-control PE-2 (N202PE) was lost off Florida due to elevator trim tab flutter 12 July 1971 but there are places online that say N201PE, the PE-1, is still dismantled in storage somewhere...?

I don't have a source for this but I had to share this cool photo of both PA-48s:
Piper Enforcers by Zac Yates, on Flickr

[Dan Jones]

They did, and called it the A2D Skyshark, and it didn't turn out to be so simple!

August

Well, there you go. Ask a silly question...

[Jim MacDonald]

Thanks for the info, Zac. Wonder what happened to the engine on the one offered for exchange?

Mac

[Randy Haskin]

I believe that three original P-51Ds were used as donor airframes for the Enforcer prototypes.

Not accurate.



Cavalier built the Cavalier Turbo Mustang III out of Mustang parts from Cavalier's parts stock, and attached the identity of N6167U to the end product.

Cavalier further modified N6167U into what eventually became the Piper PE-1 Enforcer (N201PE).

Piper built the PE-2 Enforcer (N202PE) up from a bare P-51 fuselage center section (ID unknown) and a bunch of Mustang parts out of Cavalier's former parts stock that were heavily modified.

In the 1980s, Piper built the two PA-48 Enforcers (N481PE and N482PE), which were a different design than the PE-1 and PE-2, from all new metal. The new-builds used some NOS Mustang parts (primarily small fixtures, the gear trunnions, the canopy rail.).

So, at best, one could claim that *two* Mustangs were "donors" for the entire Enforcer project...but even then that's not accurate, as the PE-1 and PE-2 were built out of ex-Cavalier parts stock (and not complete aircraft). Cavalier's parts stock came from many different sources that Cavalier purchased, from new-old-stock NAA parts, to parts culled from Mustang wrecks, to non-flyable parts that were overhauled/rebuilt, to complete airframes that were broken down into parts.

[Randy Haskin]

Thanks for the info, Zac. Wonder what happened to the engine on the one offered for exchange?

The engines and gearboxes were all USAF-owned equipment that were essentially loaned to the PA-48 test program.

[Randy Haskin]

but there are places online that say N201PE, the PE-1, is still dismantled in storage somewhere...?

Yes, still privately owned and in non-flyable storage.

[Randy Haskin]

I'm wondering if "not airworthy or suitable for flight purposes" means that one of the conditions of sale/trade is it isn't flown.

I sure hope not. Would be a shame to NOT see it in the air again. And I'll bet it would find plenty of paying customers for rides.

One of the big problems with the entire Enforcer program (and all 4 airframes) was the gearbox.

It was custom designed and constructed by Lycoming, originally for the YAT-28E program, and later used on all of the Enforcers. Numbers are tough to pin down, but somewhere between 4 and 6 of the gearboxes were made in total (with two of them being lost in the YAT-28E and PE-2 crashes).

The gearboxes had a poor design, which manifested itself in requiring complete rebuilds about every 30 hours (some sources say every 25 hours). They were also geared "wrong" for the PA-48s, as they flew a lot slower than predicted -- one of the items that Piper would have needed changed/fixed had a "production" Enforcer gone forward.

The engines and gearboxes were all owned by the USAF, and were taken back from Piper when the program was done. I don't know the whereabouts of any of them, or if one was even hanging on the front of either N481PE or N482PE while they've been displayed with the AF.

The reason the PE-1 Enforcer is sitting in storage unflyable is because it has no engine and no gearbox. The Lindsay family went through a considerable effort in the 1980s to find and recover at least one of the gearboxes from the boneyard at Davis Monthan, but faced a huge amount of bureaucratic pushback from every governmental agency involved, and came out empty handed. This is the same reason that the YAT-28E warbird project has sat non-flying for a decade or more -- no engine, no gearbox.

Even if someone *did* get their hands on one of these gearboxes, the 30-hour time between overhaul would make it completely financially impractical to fly for fun or for show. Which pilot would want to volunteer to ferry or display the single-engine airplane that needs a complete overhaul in that short of a timeframe?

Maybe someone with the right size checkbook could make it happen, but I wouldn't expect it.

Last edited by Randy Haskin on Sun Aug 30, 2020 12:22 pm, edited 2 times in total.

[Randy Haskin]

And, just as a coda, there's no such thing as a "PA-48E".

They were just PA-48s.

[blue3992]

Even if someone *did* get their hands on one of these gearboxes, the 30-hour time between overhaul would make it completely financially impractical to fly for fun or for show. Which pilot would want to volunteer to ferry or display the single-engine airplane that needs a complete overhaul in that short of a timeframe?

Maybe someone with the right size checkbook could make it happen, but I wouldn't expect it.

Interesting stuff.

Do you know any of the background on the gearbox? What is it that makes the gearbox so fragile? Also, putting gearboxes on turboprop/turboshaft engines has been done elsewhere (as far as I know). Was there something special about the PA-48 application that was unique that made it difficult to come up with a good design (the narrow shape of the forward fuselage, maybe)?

In the ~40 years since the Enforcers last flew, wondering if any other turbprops have been designed that would have a gearbox that could be reused on the Enforcer (with some modification, of course)?

[marine air]

Honestly, I would scrap the T-55 and start over from scratch , firewall forward. I think you could put a PT-6 or PW 100 Turboprop on the PA-48. The PT-6 models range in power from 580 to 1,940 shp. That would be plenty. The King Airs have a fuel tank in the nacelles that is fed by the wing tanks. This would add a lot of weight firewall forward. Maybe the PT-6 exhausts could be ducted through some Merlin style exhaust ports. I don't think the exhausts on the PT-6 turboprop (King Air) add any thrust on the King Air. Propellors are available in three, four and five bladed models.This application could also be used on the T-28 if anyone thought there could be a market for it.
I've always thought there might eventually be a market for a turbo-prop P-51 conversion.

[Randy Haskin]

Do you know any of the background on the gearbox? What is it that makes the gearbox so fragile?

All I know is that it was designed and built by Lycoming for the YAT-28E in the mid 60s, and then appropriated for the iterations for the Enforcer. The PA-48 program was on a tight budget, so using what existed was necessary even though they knew it was a weak point in the overall aircraft and would need a fix in a further iteration. Even the use of the T-55 engine was for financial and time expediency, as they planned on a different engine in a production aircraft as well.

From an engineering perspective, I don't know specifically what the weak points of the gearbox were, but they weren't minor.

[Randy Haskin]

I've always thought there might eventually be a market for a turbo-prop P-51 conversion.

If there ever was such a market, it only existed in the 50s and 60s when Mustangs were "working" aircraft.

As museum pieces today, I can't think of a reason someone would do it, as it would destroy the reason they are worth multi-millions to begin with.

Recall that there have been several "replica" Mustangs that have been proposed and built to varying levels over the years (Cameron P-51G, for example) that could have worn turboprops, and haven't found a market.