Jet A conversions for Mooney air frames??

[kbreehne]

So are any of the newly designed Jet A burning manufacturers being mounted on the front of say a M20K of which I have or a M20J?  These are popular are frames with overall low time and according my A&P buddy also a former Moomey service Technician able to take upto 300ish HP before the tail becomes the week link.  I see this type of conversion as a massive improvement which would add of course speed, water cooling & a better resale around the globe since 100LL is super hard to get anywhere but the US and it is having trouble here & in the future.  Looking forward to some great chat.

Karl  -  N231AK

[Fly Boomer]

13 minutes ago, kbreehne said:

So are any of the newly designed Jet A burning manufacturers being mounted on the front of say a M20K of which I have or a M20J?  These are popular are frames with overall low time and according my A&P buddy also a former Moomey service Technician able to take upto 300ish HP before the tail becomes the week link.  I see this type of conversion as a massive improvement which would add of course speed, water cooling & a better resale around the globe since 100LL is super hard to get anywhere but the US and it is having trouble here & in the future.  Looking forward to some great chat.

Karl  -  N231AK

A number of shortcuts have been tried -- some more successful than others.  One I have been following for at least 20 years is https://www.deltahawk.com/ which is a clean-sheet design.  They have been inching forward, but certification and production seem to be perennially just out of reach.

[A64Pilot]

Issue with any Diesel conversion that I have seen is $$$, for the overwhelming majority of 4 cyl Mooney’s it’s likely WAY more than the aircraft’s value is.

I don’t know because I’ve never looked, but I doubt the value increases by anywhere near the cost of the STC.

Other detractors is at least when I was curious, most had TBR’s not TBO, the R stands for replace so when your engine times out or gets tired, you throw it away and buy another.

But finally what would really concern me is that most of the Diesel engine manufacturers have gone out of Business.

I had a Dealer years ago that was converting new 172’s as fast as they could and selling them to Africa, then the engine manufacturer went away. I guess there is no 100LL in Africa?

About the same time Maule Certified a Diesel, but before they could sell any, the engine manufacturer went away, maybe they were the same manufacturer I don’t know, but the concern of the engine you just paid way over 100K for being orphaned would concern me.

 

[bigmo]

Ive ridden in the Tecnam P2010 with the TDI. Brilliant aircraft. Amazing that they managed certification with a wide range of engines. Fuel burn is unbelievable, and range is WAY beyond bladder range (like 12-14 hours).

I don’t know the long term ownership costs of that diesel Continental, but the flying experience was A+. Ive seen a few go for sale in the 400’s. I mean, that’s out of my price range…but it’s semi “normal”.

[Jsno]

Austro makes one for the Diamond aircraft.  168 HP but about 100 lbs heavier than an IO360.  

[bigmo]

The Continental is only 350 pounds and even though it's 170hp, it makes almost 400 ft/lbs of torque. I don't think I've seen a bunch of torque figures for traditional gas burners, but 400 pounds of torque seems like a lot.

I'm sure it'll be a while before this takes off (pun) in the US and Europe, but in austere fuel regions - a one fuel solution with a no compromises motor would be stellar. 

[T. Peterson]

26 minutes ago, bigmo said:

The Continental is only 350 pounds and even though it's 170hp, it makes almost 400 ft/lbs of torque. I don't think I've seen a bunch of torque figures for traditional gas burners, but 400 pounds of torque seems like a lot.

I'm sure it'll be a while before this takes off (pun) in the US and Europe, but in austere fuel regions - a one fuel solution with a no compromises motor would be stellar. 

I am no engineer, but is torque not more important in a low revolution engine than a high revolution engine? This may be apples to oranges and I may be demonstrating colossal ignorance, but I am thinking of a motorcycle engine. The crotch rockets make crazy horsepower, but they are spinning 10 to 14,000 rpm to do it and you have to row the gearbox to keep the rpm up. The cruisers can’t begin to match the horse power running 3 to 5000 rpm, but they have stump pulling torque requiring much less shifting. I’m not sure how that relates to our airplanes, but our max rpm is 2700 which leads me to believe that torque would be more important than horsepower and thus very suitable to a diesel engine. 

 I would welcome the correction/ insight of our resident engineer/tech guys. I know the diesel is heavy and expensive. I am curious about the hp vs torque angle. Please be nice to me. I know I am way over my head when I postulate anything technical!!

[Will.iam]

48 minutes ago, bigmo said:

The Continental is only 350 pounds and even though it's 170hp, it makes almost 400 ft/lbs of torque. I don't think I've seen a bunch of torque figures for traditional gas burners, but 400 pounds of torque seems like a lot.

I'm sure it'll be a while before this takes off (pun) in the US and Europe, but in austere fuel regions - a one fuel solution with a no compromises motor would be stellar. 

Yea all that torque pulses doesn’t play well with propellors of today. Like a hammer, the vibrations would yet be another potential problem that needs testing to verify.   

[EricJ]

Torque and hp are related.   For torque in ft-lbs and power in hp, the relationship is hp = (torque * rpm)/5252.    This is why dyno plots showing both torque and hp always have the curves cross at 5252 rpm, because they're the same at that rpm.    Many engines with well-designed intake and exhaust systems will produce more or less constant torque across their operating range, which means that generally hp increases linearly with rpm.   This is why max power happens at or near max rpm, and why many applications get more power by spinning the engine faster.     This is also why many aviation engine applications, especially experimentals these days, use gear reduction so that the engine can spin faster than the propeller so that they can produce more power.

Diesels naturally make a lot of torque, but often can't spin fast enough to generate a lot of power.   In a vehicle this is made useful with gearing.   In an aircraft if it spins fast enough to turn a prop, that's already ok.    In WWII the main applications for needing high torque at low RPM were aircraft and tanks, so many tanks also used aircraft engines (e.g., the M4A1 Sherman used the same Wright engine as the C-47, the M3A1 Stuart used a 7-cylinder Continental radial, and the M22 Locust used a Lycoming O-435).  

An IO-360 making 200 hp at 2700 rpm makes (200*5252)/2700 = 389 ft-lbs of torque.   If you've ever looked at a typical small aircraft cylinder and piston compared to an automobile engine, it's clear airplane engines are made for low rpm torque, since they can't spin very fast or the propeller loses efficiency.

[bigmo]

This is a short video on Tecnam’s TDI. Ive seen a couple of these in the wild now…this isn’t a “coming soon” plane. If an uncle dies and leaves me a couple hundo, I’m a buyer!

There’s no overhaul options yet, but the TBR cost is $90K which isn’t THAT bad. I think TBR is 1800, but elected to climb to 2100 soon.

130 knots on 6ish gph of Jet-A is pretty amazing. Again, I think this is a GREAT idea where markets don’t support 100LL. And, I mean, this engine is made by Continental - not Bob’s Engines.

 

[Will.iam]

But why are the diesels to replacement and not overhaul? Why can’t you still use the crankshaft case etc?

[T. Peterson]

2 hours ago, EricJ said:

Torque and hp are related.   For torque in ft-lbs and power in hp, the relationship is hp = (torque * rpm)/5252.    This is why dyno plots showing both torque and hp always have the curves cross at 5252 rpm, because they're the same at that rpm.    Many engines with well-designed intake and exhaust systems will produce more or less constant torque across their operating range, which means that generally hp increases linearly with rpm.   This is why max power happens at or near max rpm, and why many applications get more power by spinning the engine faster.     This is also why many aviation engine applications, especially experimentals these days, use gear reduction so that the engine can spin faster than the propeller so that they can produce more power.

Diesels naturally make a lot of torque, but often can't spin fast enough to generate a lot of power.   In a vehicle this is made useful with gearing.   In an aircraft if it spins fast enough to turn a prop, that's already ok.    In WWII the main applications for needing high torque at low RPM were aircraft and tanks, so many tanks also used aircraft engines (e.g., the M4A1 Sherman used the same Wright engine as the C-47, the M3A1 Stuart used a 7-cylinder Continental radial, and the M22 Locust used a Lycoming O-435).  

An IO-360 making 200 hp at 2700 rpm makes (200*5252)/2700 = 389 ft-lbs of torque.   If you've ever looked at a typical small aircraft cylinder and piston compared to an automobile engine, it's clear airplane engines are made for low rpm torque, since they can't spin very fast or the propeller loses efficiency.

Very interesting and informative. Sounds like a diesel would fit the bill. Is the weight and expense the major detractors? In other words if it wasn’t for the expense and weight, would the diesel actually be a preferred option?

[McMooney]

If i had the money i'd take a shot at converting one of the new turbo diesels for experimental use.

chevy lz0 inline 6, bit heavy but power band is exactly at current engine / prop numbers, no psru necc.  well you'd probably need some sort of unit to handle prop alignement and maybe heavy bearings to take prop loads.

[Gee Bee Aeroproducts]

I have supplied various installations for prototypes.

stc and product liability is the hidden cost that will keep anything new from going forward.

My list of projects 

Adams aircraft 

Kestrel aircraft 

lancair

Columbia / Cessna 

Toyota 

I would like to see a new larger Rotax 

[A64Pilot]

9 hours ago, Will.iam said:

But why are the diesels to replacement and not overhaul? Why can’t you still use the crankshaft case etc?

Good question, as an IA it turns me away from such an engine, just because I can’t save money and do my own overhaul. New private buyers will likely never face replacement, but I can’t afford an airplane that costs the same as my house, so I have to buy used.

I suspect liability, Jim Bob overhauls an engine, it fails, pilot dies and as Jim Bob has no assets the manufacturer is sued, sure so is Jim Bob but he is judgement proof.

It’s a Jury trial and of course they feel sorry for the poor crying Widow with three children and a big judgement is given so she can live and raise the children in the manner they were accustomed.

This is supposition but as Lawsuit happy as we are I suspect there is a grain of truth there.

[A64Pilot]

9 hours ago, T. Peterson said:

Very interesting and informative. Sounds like a diesel would fit the bill. Is the weight and expense the major detractors? In other words if it wasn’t for the expense and weight, would the diesel actually be a preferred option?

There are a number of detractors, for example Diesels have a very high torque pulse due to the high compression, this wrecks transmissions in trucks so dual mass flywheels etc are used to absorb the pulse, airplane props and prop hubs take punishment, NVH for a Diesel is high. As they are a compression engine often they can’t restart at high altitudes, Jet-A is a very dry fuel and is hard on injection pumps and injectors. Go-arounds can be problematic as there is turbo lag, cooling can be an issue. Some have very high drag cowlings to introduce enough cooling.

Weight of course comes off of useful load.

Germans in WWII built a Diesel bomber I believe as it’s sort of ideal for a big airplane, but weight I think was the detractor. https://www.historynet.com/luftwaffes-high-flying-diesel/ The Junkers design as a two stroke opposed piston engine was more advanced than today’s Diesels, in the 1930’s

The 1930’s Zeppelins had Diesels so Aviation Diesels aren’t a new concept.

Sure if weight and money aren’t a detractor a Diesel may fit the bill, but until they become more mainstream even if I could afford it I would stay away just due to parts availability and lack of trained mechanics.

[PeterRus]

15 hours ago, bigmo said:

Ive ridden in the Tecnam P2010 with the TDI. Brilliant aircraft.

Shh, please, don't tell anyone about the tecnams! 

[A64Pilot]

13 hours ago, EricJ said:

Torque and hp are related.   For torque in ft-lbs and power in hp, the relationship is hp = (torque * rpm)/5252.    This is why dyno plots showing both torque and hp always have the curves cross at 5252 rpm, because they're the same at that rpm.    Many engines with well-designed intake and exhaust systems will produce more or less constant torque across their operating range, which means that generally hp increases linearly with rpm.   This is why max power happens at or near max rpm, and why many applications get more power by spinning the engine faster.     This is also why many aviation engine applications, especially experimentals these days, use gear reduction so that the engine can spin faster than the propeller so that they can produce more power.

Diesels naturally make a lot of torque, but often can't spin fast enough to generate a lot of power.   In a vehicle this is made useful with gearing.   In an aircraft if it spins fast enough to turn a prop, that's already ok.    In WWII the main applications for needing high torque at low RPM were aircraft and tanks, so many tanks also used aircraft engines (e.g., the M4A1 Sherman used the same Wright engine as the C-47, the M3A1 Stuart used a 7-cylinder Continental radial, and the M22 Locust used a Lycoming O-435).  

An IO-360 making 200 hp at 2700 rpm makes (200*5252)/2700 = 389 ft-lbs of torque.   If you've ever looked at a typical small aircraft cylinder and piston compared to an automobile engine, it's clear airplane engines are made for low rpm torque, since they can't spin very fast or the propeller loses efficiency.

For anyone who confuses what torque is, the above is one of the best explanations I’ve seen.

Torque is important for say getting a heavy truck moving as at low or zero speed they are gear bound, by that I mean the motor can’t turn up high RPM until the truck reaches a speed where the gear allows it.

An aircraft has a propellor of course, a prop can and does slip and allows significantly high RPM prior to the aircraft beginning to roll, a constant speed prop of course allows even higher static RPM, so low RPM torque isn’t as relevant in an airplane as it is in a heavy truck.

Torque is simply a twisting force, but torque alone doesn’t do any work as there is no movement, combine torque with speed of movement and you get HP.

As direct drive aircraft engines are very much RPM restricted, in order to get more HP as you cannot raise RPM you have to increase torque, so they are in fact pretty high torque engines.

However by displacement they are actually pretty low power motors. Our IO-360 at 200 HP is decently high compared to many aircraft engines, but we only produce roughly .55 HP per cu in. Long ago bikes and I believe cars by now have eclipsed 100 HP per Liter which is 1.65 HP per cu in. largely as they are not RPM restricted.

But also an airplane motor can make full power for a long time whereas Auto’s and bikes cannot.

RPM and torque are inseparable torque is just force applied, HP is force applied with movement, noting more complex than that. 

Edited Tuesday at 03:13 PM by A64Pilot

[Pinecone]

15 hours ago, EricJ said:

In WWII the main applications for needing high torque at low RPM were aircraft and tanks, so many tanks also used aircraft engines (e.g., the M4A1 Sherman used the same Wright engine as the C-47, the M3A1 Stuart used a 7-cylinder Continental radial, and the M22 Locust used a Lycoming O-435).  

 

Slight correction.  the M4 and M4AI Shermans used the R-985, which is the same engine as the Beech 18, not the C-47.

[1980Mooney]

7 hours ago, PeterRus said:

Shh, please, don't tell anyone about the tecnams! 

There are 2 used P2010 TDI 170 HP for sale on Controller,  You can buy them for $530,000 to $605,000.

I looked at the P2010 TDI POH.  Max continuous power is 91% or 155 HP.  At 10,000 ft. and 91% power it will do 140 KTAS burning 8.7 GPH.  It is a 4 seater with 838 lbs. UL. zero fuel. 

I can think of a lot of other used planes to buy for that kind of money.  And I think that most M20C running lean and low RPM can do 140 KTAS at 9 GHP and do it with way higher UL.

Don't worry - I think that your secret is safe......

 

Edited Tuesday at 10:41 PM by 1980Mooney

[Hank]

4 minutes ago, 1980Mooney said:

There are 2 used P2010 TDI 170 HP for sale on Controller,  You can buy them for $530,000 to $605,000.

I looked at the P2010 TDI POH.  Max continuous power is 91% or 155 HP.  At 10,000 ft. and 91% power it will do 140 KTAS burning 8.7 GPH.  It is a 4 seater with 838 lbs. UL. zero fuel. 

I can think of a lot of other used planes to buy for that kind of money.  

Don't worry - I think that your secret is safe......

You just described my C!! Except my useful load is 130 lb higher. For that price, you could buy a second C so you're never down for annual; lease some land; build a hangar; pay for all required inspections, typical maintenance and fuel for several years! Maybe ten or twelve, longer if you only buy one C.

[1980Mooney]

22 hours ago, bigmo said:

The Continental is only 350 pounds and even though it's 170hp, it makes almost 400 ft/lbs of torque. I don't think I've seen a bunch of torque figures for traditional gas burners, but 400 pounds of torque seems like a lot.

I'm sure it'll be a while before this takes off (pun) in the US and Europe, but in austere fuel regions - a one fuel solution with a no compromises motor would be stellar. 

Max Continuous power per the POH is 91% or only 155 HP.  

[1980Mooney]

2 minutes ago, Hank said:

You just described my C!! Except my useful load is 130 lb higher. For that price, you could buy a second C so you're never down for annual; lease some land; build a hangar; pay for all required inspections, typical maintenance and fuel for several years! Maybe ten or twelve, longer if you only buy one C.

A lot of people say that the M20J was the best plane that Mooney ever built, but in reality, maybe it really was the M20C.

[PeterRus]

6 minutes ago, 1980Mooney said:

Max Continuous power per the POH is 91% or only 155 HP.  

What's max continuous power for a C? How many doors does a C have? What's typical C avionics?

Edited Tuesday at 10:51 PM by PeterRus

[1980Mooney]

1 hour ago, PeterRus said:

What's max continuous power for a C? How many doors does a C have? What's typical C avionics?

The important point is that the M20C at 10,000 ft will cruise at 140 KTAS using 70% power requiring 9 GPH.  70% of the 180 HP Lycoming is only 126 HP and well within any max continuous concern.  And doing it with nearly 1,000 lbs UL.  The Tecnam requires 155 HP to do the same thing at that altitude while hauling about 150 lbs less UL.  The GPH of both planes is within spitting distance of each other BUT since Diesel/JP weighs 10% more than AVGAS, the Tecnam needs 57 lbs/hour fuel vs the M20C that only needs 54 lbs/hour.

Avionics?  It doesn't make the plane go faster.  Some C's have great upgrades.  Even with a basic autopilot, an old Garmin 430W and an iPad functionality is only marginally different.  Granted a flat panel looks great and creates a lot of "physic appeal". 

Don't get me wrong, I would love the look feel of a new plane too. But a $400,000 premium for 2 extra doors?  Besides, at that UL it is really mainly a 2-person plane.

This is the struggle for General Aviation today.  Modern aircraft manufactures are trying to make something "better" - in this case a carbon fiber fuselage on a metal wing with a diesel engine. Agreed that you get a wider cabin and maybe an extra door or 2.  But performance is no better than a 60 year old Mooney.  There is a new Tecnam P2010 TDI "0" hours on Controller for sale for $683,000.  The new GA market is for millionaires - others need not apply.

 

Edited Tuesday at 11:54 PM by 1980Mooney