Need some advice on a purchase

Trigear? Taildragger? Fixed pitch prop? Which Engine? ...anything related with model selection considerations and questions about buying a Maule
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norcal64d
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Need some advice on a purchase

Post by norcal64d »

I am looking at MX-7-180A, and it has a couple things that jumped out at me. Its only been flown 73 hours since 2006, so in my mind it has the potential for some corrosion inside the engine, particularly the cam. It only has 500 hrs since new on the engine, but it has been doing some very infrequent flying for years and years in the great lakes region.

The second issue is that in 2001, with 250 hrs on the engine and prop, the prop was changed with no explanation and the log shows the engine being reinstalled after an overhaul with zero records on who did the overhaul, why it was done, or if any parts were changed. The local FSDO says there is not enough data to consider it an overhaul so an entry was made saying the engine should be considered to not have an overhaul and time since new applies.

I'm curious what the consensus is, in my mind it probably needs to be sold as a plane with an engine that probably only has 200 hrs left before it needs some work, and I'm afraid that for resale value, the log issue will scare off alot of people. Am I being paranoid? The rest of the plane looks damn near brand new!

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Stinger
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Post by Stinger »

I have a 1994 MX-7-180A.
When I bought it in 2016, it was from a guy in Arizona. I tried to buy it earlier in the year from a guy in Wisconsin, but the Arizona guy beat me to it.
It flew regularly from 1994-2003 and accumulated 550 hours. The first ~400 hours was from the original owner in Corpus Christi, TX, before he sold it to the Wisconsin owner in 1997. The Arizona guy bought it with 595 hours. I bought it 4 months later with 614 hours.
Looking through the engine logs, there was a couple periods where it didn't fly at all for 3 years, only the annual. There was a few annuals missing (2009, 2010, 2011, 2014.)

I had the same worry you did, where the insides of the engine might not be in very good shape, but that hasn't been the case for me.

So far it's been mostly maintenance-free. The 2018 annual was the only engine issue I've had where one of the cylinders had low compression. Was caused by buildup on the exhaust valve.

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Post by tellicovillage »

I think if you had the money for a new/rebuilt engine soon in the deal I would not be afraid of it. Once the engine is new I don't think past engine logs will matter much if at all. Mine started making metal at about 1780 hrs and 20 years. I took the opportunity to change mine to the C1F and a constant speed prop which (to most) is a much more desirable aircraft. I would check out the air-frame for any signs of damage. Good Luck hope you found a deal!

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Post by andy »

The prop was probably changed and the engine removed and reinstalled due to a nose-over. Without overhaul records, you can't consider it overhauled. Lack of more detailed logbook entries is a warning flag in my mind. If the plane was nosed-over, there probably was no engine damage when the prop stopped. However, when you can't trust one thing in the logbooks, everything else in them is suspect.
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TomD
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Post by TomD »

Did this bird pop up in another "planning to buy" thread?

In which State is it located?

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Post by Dale Smith »

I don't think you are wrong to think that sitting could have a negative affect on an engine. I regularly see rust forming on the flywheel of my plane in as little as 2 weeks in the winter time. I have seen it go both ways. Engines that fly very little that make TBO and others that don't. If there is no explanation of what was done to the engine, it should raise an eyebrow. If the price could be adjusted accordingly, and you go into it knowing that it might need an engine you are mentally prepared for it. I have seen 0-320's in 172's go 3000 plus and still be running and checking out alright. take for granted those are flight school airplanes that are flying 500-600hrs per year though...


Best of luck!
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norcal64d
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Post by norcal64d »

Thanks for all the replies, gents. Tom, the aircraft is in Michigan and I am not certain if it has come up in any other threads than being listed in the For Sale section on the forum here.

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Post by TomD »

The one I was thinking of was in the Pacific NW.

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Post by Narwhal »

Looks like that green MX7-180 in Michigan was sold to someone!

Amazing how few maules there are for sale, we're all looking at the same ones. The logbook situation on so many of these airplanes is disgusting. I am almost considering just buying a brand new one. There don't seem to be many good MX7-180's for sale. Maybe it is just a rare type of Maule. I cannot justify the fuel burn, maintenance and overhaul costs of an O-540 given my purely recreational use of an airplane. Then again, I guess the 100K+ i would save on buying a really nice used 2010's M7-235 vs a Brand new MX7-180 would go a long way toward operating costs.

The red MX7-180 on maule air texas now says it was originally an M5, destroyed in the mid 90's and rebuilt by the factory as an MX7-180? WTF?

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Post by Andy Young »

Maules are “Mr. Potato Headâ€￾ airplanes. The model designations indicate what combination of fuselage, wing, engine and landing gear a particular plane has. If someone changes the combination such that it matches a different model, it becomes that model. A surprising amount of mixing and matching can be done relatively easily.

Narwhal wrote:Looks like that green MX7-180 in Michigan was sold to someone!

Amazing how few maules there are for sale, we're all looking at the same ones. The logbook situation on so many of these airplanes is disgusting. I am almost considering just buying a brand new one. There don't seem to be many good MX7-180's for sale. Maybe it is just a rare type of Maule. I cannot justify the fuel burn, maintenance and overhaul costs of an O-540 given my purely recreational use of an airplane. Then again, I guess the 100K+ i would save on buying a really nice used 2010's M7-235 vs a Brand new MX7-180 would go a long way toward operating costs.

The red MX7-180 on maule air texas now says it was originally an M5, destroyed in the mid 90's and rebuilt by the factory as an MX7-180? WTF?

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Post by Andy Young »

On the fuel burn subject, one can always run the engine at lower power, and achieve a similar fuel burn to that of a smaller engine. I often travel in the company Taylorcrafts and Pacers with my M-6-235. To stay at their speed (about 85 mph) I am at 2000 rpm and 11-13â€￾ manifold pressure, burning 7.5 gph. In my normal cruise of 2400 rpm and 24â€￾, I go about 125 mph burning 12 gph. That’s on bushwheels; on 8.50s, I go 140 mph at the same settings and burn.
Narwhal wrote:Looks like that green MX7-180 in Michigan was sold to someone!

Amazing how few maules there are for sale, we're all looking at the same ones. The logbook situation on so many of these airplanes is disgusting. I am almost considering just buying a brand new one. There don't seem to be many good MX7-180's for sale. Maybe it is just a rare type of Maule. I cannot justify the fuel burn, maintenance and overhaul costs of an O-540 given my purely recreational use of an airplane. Then again, I guess the 100K+ i would save on buying a really nice used 2010's M7-235 vs a Brand new MX7-180 would go a long way toward operating costs.

The red MX7-180 on maule air texas now says it was originally an M5, destroyed in the mid 90's and rebuilt by the factory as an MX7-180? WTF?

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Post by Narwhal »

Thanks for the responses!

here is the ad for the red one:
http://www.mauleairtexas.com/aircraft/l ... 80B&id=390

My main question is how can there be 300 hours on the airframe (since it was destroyed and rebuilt as an MX7 at the factory, according to the ad) yet 1000 hours on the engine?

If the aircraft was destroyed wouldn't that imply damage to the engine as well? Could the engine have been salvaged or purchased from another aircraft with 700 hours already on it? Is it possible that it is the original engine?

I mean no disrespect to the seller, genuinely curious. I could well be interested in this airplane but have already had to pass on several potential airplanes due to huge logbook discrepancies and improperly documented major repairs. Maybe I am being unrealistic, but I don't want to be involved in pencil-whipped airplanes. Involvement of the Maule factory is reassuring on this one though, I have to assume they did things right.

Here is what happened that resulted in the aircraft's destruction as an M5:
"On September 10, 1995, at 1145 central daylight time, a Maule M- 5, N5669P, was substantially damaged during its initial takeoff roll when it collided with a Pitts, N79DG, who was landing on the same runway at Belvidere LTD Airport, Belvidere, Illinois. The Pitts was also substantially damaged. The pilot of the Maule reported no injuries and the passenger reported minor injuries. The pilot of the Pitts reported no injuries. The 14 CFR Part 91 flights operated in visual meteorological conditions without flight plans.

In a written statement, the pilot of the Maule reported that after performing a complete engine run-up and cockpit check, he taxied the airplane in preparation for takeoff. The pilot stated that he stopped the airplane on an area between the taxiway and runway 12 to check for landing traffic. The pilot stated that he saw several airplanes and decided to wait for two arrivals. After these airplanes landed and cleared the runway, the pilot taxied his airplane onto runway 9. The pilot stated that he had not seen any other additional traffic before positioning his airplane on the runway. The pilot applied full power for takeoff. At approximately 100 feet down the runway, N5669P was impacted by the Pitts, N79DG, which was landing on runway 09.

During a telephone interview, the pilot of the Maule stated that before each takeoff he normally performs several 360 degree turns in his tailwheel airplane as a precaution to check for traffic. But he had not this day. The pilot also stated that he did not hear the other airplane make a position call on the unicom frequency while it was on final approach.

The pilot of the Pitts reported that while en route to Belvidere, he requested the winds and active runway at Galt Airport, Greenwood, Illinois, to ensure that his radio was transmitting and receiving. The pilot stated that Galt responded clearly with the information.

The pilot of the Pitts stated that upon his arrival at Belvidere, he saw two other airplanes in the traffic pattern. One was on a left downwind for runway 09 and the other was in the pattern for runway 12. The pilot entered the pattern behind the traffic for runway 09 and made a radio transmission on Belvidere's unicom frequency announcing his position of downwind for runway 09. The pilot continued to follow his traffic and observed the traffic land as he was on a left base. The pilot made a position call on base. The pilot stated that he saw the second original traffic land on runway 12 as he turned the airplane onto final approach. The pilot stated he announced his final approach over the unicom and entered a left slip as he watched to make sure his traffic was clearing the runway. "As I began to transition, I heard a radio transmission indicating the aircraft was departing [runway] 09 at Belvidere. At that second, I felt impact," the pilot stated. The airplane rolled to the left and impacted the ground inverted."
In regard to pulling back on O-540 to lower power settings when speed is not important; could the same thing not be done with an O-360 (pulling it back to O-320 levels of fuel consumption?). Also, I would speculate that fuel is merely a drop in the bucket compared to the eventual overhaul cost and maintenance considerations of an O-540. Maybe I am wrong. I would certainly be OK with an O-540 but I am acquiring the aircraft in a partnership and my partner has an aversion to high operating costs.

I know nothing and am here to learn.

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Post by andy »

FAR 91.421 only addresses "zero time" for engines that are rebuilt by the manufacturer or an agency approved by the manufacturer. It doesn't include airframes. FAR 91.417 requires that transferred maintenance records include the total time in service on each airframe, engine, propeller or rotor. It's possible that the engine wasn't damaged during the collision but the airframe was damaged enough for the insurance company to declare it destroyed. I guess you can say anything that you want in an advertisement without violating the FARs but the logbooks have to show the airframe total time.
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Post by gbarrier »

If you can't prove the necessary inspections after prop strike then tear it down. If not, and been sitting like that it will probably bite you in about 300 hours due to corrosion anyway. Just my opinion.

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Post by andy »

Andy Young's point is well-taken about being able to reduce fuel burn by pulling back power on a 540. Your point is correct about being able to do the same thing with a 360. However, you can't get more horsepower out of a 360 when you need it. I've owned my MX-7-180 for 21 years and have around 1,800 hours in it. 99% of the operations have been fine with a 180 hp engine but there have been times that I wished for the additional horsepower, especially during climb out on a hot humid day with a heavy load. Deciding on a 180 hp or 235 hp engine is a matter of your intended operations. If you only plan to fly off airstrips over 1,500 feet long at relatively low density altitudes and less than maximum gross weight, then a 180 hp engine will save you money on fuel and overhaul. If you want to fly off airstrips less than 1,500 feet long with obstacles at the ends (like trees) or fly in the high country, then a 235 hp or greater would be a better decision.
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