SonexBuilders.net

Dear Sonex community

I have a question regarding the MPI for a Sonex. i cant seem to find any information. It will be much appreciated if someone can shed some light on this topic. Are we looking at the normal 100 hr MPI and what is all involved in this MPI as well as an estimated cost.

As you can derive i am not a Sonex owner...Yet...but i am in the research part seriously about purchasing a Sonex.

Any input on the TBO would also be much appreciated as i am trying to calculate costings and hourly rates on the aircraft.

Hello,

I'll go ahead and admit my stupidity here; what do you mean by MPI? I fly behind Honeywell TFE731's, and on those it means Magnetic Particle Inspection, but I don't think that applies to the AeroVee.

Sorry for being a dummy here!

TBO on a homebuilt is up to the owner/operator. I don't know if you'll get an official number on that one. There are a lot of variables.

Which engine are you considering? Thanks for the post and help!

MPI means Major Periodic Inspection.
This lingo is used more in the turbine engine world, not so much around light aircraft.

Neither MPI nor TBO have any real meaning in the experimental aircraft world (unless the kit or engine manufacturer has a recommendation.)

I just finished listening to a webinar given by John Monett about the aerovee engine... the webinar should be up on the EAA website in a few days I believe. If you want to know all about the aerovee, I do suggest you check it out when it becomes available.

The Sonex airframes, as far as I know, have no inspection requirements beyond the annual condition inspection (which the owner can do yourself with the proper paperwork.)

The question of TBO did come up from a guest during the webinar... the number 1000hrs was tossed around, as was the example of a full set of replacement cylinder heads/rings etc costing less than $300. Since the aerovee engine is a kit, the builder has the ability to both assemble and overhaul their own engine. There is no TBO on the aerovee.

I'm also new to the experimental/kit aircraft world as of last summer, and have been a corporate pilot flying turbine aircraft for the last 13 years. I bought a Waiex kit last fall, and am currently building. You probably have a lot of the same questions in your head that I had last year, so please feel free to ask away and I'll help as much as I can.

I'm sure some of the more experienced owners can offer good input as far as cost to own/operate, but my guess is after hangar rent, insurance and fuel, the costs become far more minuscule in an aircraft like a Sonex.

Rynoth wrote:I'm sure some of the more experienced owners can offer good input as far as cost to own/operate, but my guess is after hangar rent, insurance and fuel, the costs become far more minuscule in an aircraft like a Sonex.

I can certainly offer my own numbers, but take them for what they're worth...just my experiences!

1. Hangar Rent: $200 per month ($2400/year)
2. Insurance: $1000 per year ($35,000 hull value for me)
3. Fuel (100LL only): $5.80 per gallon times 5 gallons per hour: $29.00 per hour

Personally, I don't calculate oil change or engine overhaul costs given the inexpensive nature of the AeroVee. I think an oil change is a little over $20 but not enough for me to worry about. For me, those are the main costs for the project. Everything else is pocket change!

Given those prices, I guess that would work out to the following hourly costs for me:

50 hours per year = $97.00 per hour
75 hours per year = $74.33 per hour
100 hours per year = $63.00 per hour

Moral of the story here is, make sure you can share a hangar with someone, and fly your airplanes a lot! :shock: ;)

HI guys

Thnx for the replies. to give you more background from my side. I live in South Africa and the term MPI is used here for " mandatory periodic inspection" Which in our general used Aircraft where i work is 100 hours/annually.

and that is where my query originated from as we change engine oil every 50 hrs and full MPI inlcuding service every 100 hours.

To answer Michael's question, yes we are looking at the Aerovee and once we ready i do hope the Turbo's are available as we are at a very high elevation ( 5000') and density altitude can easily vary between 6000 and 7000 ft.

Anyone possibly in the states flying an aerovee at similar altitudes?

In the USA, experimental aircraft are typically required to be inspected at least annually. In the case of an experimental aircraft, this inspection is called a "condition inspection", and is required by the aircraft's operating limitations, issued by the FAA as a part of the aircraft's airworthiness certificate. The basic outline or checklist for this condition inspection is found in the FAA regulations, in Appendix D to Part 43. You can view this and all FAA regulations at http://www.ecfr.gov/cgi-bin/text-idx?c= ... tab_02.tpl

There is no other scheduled maintenance that is specifically required by regulation in most cases.

Hope this helps!

Volt,
Greetings.

Volt wrote:. . . and that is where my query originated from as we change engine oil every 50 hrs and full MPI inlcuding service every 100 hours.

The Aerovee requires an oil change every 25 hours. The valve clearances get adjusted at the same time. The good news is that it's a quick process. The oil is 20-50W racing oil for automobiles (it needs to have a high ZDDP= "zinc" content to keep this engine happy).

Volt wrote: . . . we are at a very high elevation ( 5000') and density altitude can easily vary between 6000 and 7000 ft.

Anyone possibly in the states flying an aerovee at similar altitudes?

There are people flying the Aerovee from US fields at high elevation. They will probably chime in directly, but from what I've heard they are generally happiest flying at less than full gross weight if the temperatures are high. What is deemed satisfactory depends on runway length, required climb gradient, and personal judgement.

The Aerovee (and many other VW-based engines) are great, economical powerplants for airplanes requiring modest power. Last night John Monnett gave a very interesting webcast talk on his experiences in developing the Aerovee, it should be up on the EAA web site in a few days (mentioned by Ryan, above). He discussed the ongoing turbo Aerovee development and showed some very good photos (I was unaware until last night that the latest version has the turbo tucked up behind the engine rather than below, and the intent is to make it fit all present Sonex airframes fitted with Aerovee engines). At one point he also said words to the effect of " . . . if we release this product . . .", which might have just been a slight word choice issue during an unscripted presentation. Still, the use of "if" rather than "when" at that point surprised me. Again, they are obviously continuing development and I hope things go well.

Mark

Thanx for the prompt and thorough replies. it's amazing how alike aviators across the globes are. Always keen to help another.

I too am anxious about this turbo option. Extra power is always welcome :)