If Cirrus is offering this engine, why would they not go thru the same process as they did with the Sr-22? Should holders of positions have a right to be in line first for this engine? Larry
If Cirrus is offering this engine, why would they not go thru the same process as they did with the Sr-22? Should holders of positions have a right to be in line first for this engine
It’s not being offered yet! The announcement seems to be basically the start of the process in which Cirrus will engineer the engine installation (which will also require some fuel tank cleverness, since running a tank dry on a Diesel is a big no-no). This process will take some time, and I would expect that Cirrus will offer existing customers a shot at it when they actually have some idea when it will be deliverable. But unless plans change before then, expect to emigrate to Europe if you want one early 
I assume that the limitation (initially) to Europe is 1) because demand will be greater thene due to the high cost of AvGas, and 2) because there will be no service network for the engine in the USA.
I spoke to Cirrus today about converting my SR22 position to an SR21tdi and was told that it would probably be a straight swap with approximaely the same delivery date.
This is not a definite yet and I will need to wait and see the price and performance figures.
And before you ask yes I do live in Europe 
Simon
Clyde,
Dumb question from a guy who knows nothing about diesel power. What is the big “no-no” problem or situation created when one allows the tanks to go dry on a diesel, in contrast to gasoline powered engines? Of course, both produce an attention getting and powerful silence, but what else is there in re the diesel?
Pete
If Cirrus is offering this engine, why would they not go thru the same process as they did with the Sr-22? Should holders of positions have a right to be in line first for this engine
It’s not being offered yet! The announcement seems to be basically the start of the process in which Cirrus will engineer the engine installation (which will also require some fuel tank cleverness, since running a tank dry on a Diesel is a big no-no). This process will take some time, and I would expect that Cirrus will offer existing customers a shot at it when they actually have some idea when it will be deliverable. But unless plans change before then, expect to emigrate to Europe if you want one early
I assume that the limitation (initially) to Europe is 1) because demand will be greater thene due to the high cost of AvGas, and 2) because there will be no service network for the engine in the USA.
If Cirrus is offering this engine, why would they not go thru the same process as they did with the Sr-22? Should holders of positions have a right to be in line first for this engine
It’s not being offered yet!
… but CD resp. General-Enterprises accepts already $30K downpayments… so first-come first-serve!
Dumb question from a guy who knows nothing about diesel power. What is the big “no-no” problem or situation created when one allows the tanks to go dry on a diesel
Not a dumb question, I should have explained - if you get air in the injection lines of a diesel engine, it requires that the lines be bled to purge the air. You can’t do this in the air, and the engine won’t run until you do it. So if you were to run a tank dry, the engine would stop, just like an avgas engine, but will not restart, unlike an avgas engine (assuming you haven’t run both tanks dry, in which case the type of the engine is not a big issue!)
For this reason, it seems likely that to get a Diesel engine installation certified, the two wing tanks are going to have to feed as a single tank. That’s one of the challenges that Cirrus Design will have to overcome.
Dumb question from a guy who knows nothing about diesel power. What is the big “no-no” problem or situation created when one allows the tanks to go dry on a diesel
Not a dumb question, I should have explained - if you get air in the injection lines of a diesel engine, it requires that the lines be bled to purge the air. You can’t do this in the air, and the engine won’t run until you do it. So if you were to run a tank dry, the engine would stop, just like an avgas engine, but will not restart, unlike an avgas engine (assuming you haven’t run both tanks dry, in which case the type of the engine is not a big issue!)
For this reason, it seems likely that to get a Diesel engine installation certified, the two wing tanks are going to have to feed as a single tank. That’s one of the challenges that Cirrus Design will have to overcome.
Thanks Clyde–I wasn’t aware of this either. Since I believe this may be the engine that underwent testing in a Socata single (low wing), I wonder if Socata has this problem worked out?
That being said, an SR20 airframe carrying an engine which performs as per the claims would be a world-beater.
$70K for the engine seems astounding, that’s about twice the cost of the SR22’s IO-550. If true it nullifies almost any benefit of a 3000-hr TBO. Say it ain’t so!
Not a dumb question, I should have explained - if you get air in the injection lines of a diesel engine, it requires that the lines be bled to purge the air. You can’t do this in the air, and the engine won’t run until you do it. So if you were to run a tank dry, the engine would stop, just like an avgas engine, but will not restart, unlike an avgas engine…
I’m confused–I used to have a diesel car, and don’t remember having a problem restarting when I ran out of gas…? Maybe my memory is lacking, though.
Where was the $70k rumor seen?
---------Andy
Not a dumb question, I should have explained - if you get air in the injection lines of a diesel engine, it requires that the lines be bled to purge the air.
I may be wrong but, the engine in my Ford (A PowerStroke) uses high pressure to deliver the fuel to the engine and a low pressure return line back to the tank. When the truck ran out of diesel (in steps the wife), my concerns were the same as yours. A quick phone call to the trusty diesel mechanic who promptly told me in non-engineering terms, “Put diesel in it and it will fricken start. I promise” proved me wrong. Why? I do not know exactly, but it did.
I know the return line is common place on all fuel systems. I do not know if this diesel engine has a special system to prevent vapor lock.
One concern I do have about a diesel engine in a plane is what happens if the engine does quit? Does the prop windmill?? Given the higher compression ratio of a diesel engine, would the airflow past the prop be able to turn the engine over, therefor reducing drag in a engine out scenario? Or would the prop take a 12 and 6 position and stay put?
Where was the $70k rumor seen?
Nevermind, I found it------Andy
I know the return line is common place on all fuel systems. I do not know if this diesel engine has a special system to prevent vapor lock.
Well, I’m only going on what I’ve been told - and I used to have a diesel generator that had exactly this problem - run it dry and it would not go until the injection line (single cylinder) was bled.
Given the higher compression ratio of a diesel engine, would the airflow past the prop be able to turn the engine over, therefor reducing drag in a engine out scenario? Or would the prop take a 12 and 6 position and stay put?
If it did stay put, that would be good - a windmilling prop has more drag than a stationary one.
It is too early to tell but here is my $.05 worth.
As soon as you slow to about 80 or so it will come to a stop which is good, this will reduce the drag. I don’t know where it will stop but you can always save the prop by kicking the starter until it shows 9 and 3 for a two bladed and for the 3 bladed bring one at 6 o’clock and you just saved yourself about $3K if the nose gear folds. Why is it that no one has mentioned the size of the battery that will be required to start this high torque engine in the winter things are cold and stuburn… Diesel engines just keep on turning, would be nice if they figured out how to keep the vibrations down low like a rotary engine. Have a great Cirrus day Jet A or 100LL and keep the dirty side down.
Woor
Not a dumb question, I should have explained - if you get air in the injection lines of a diesel engine, it requires that the lines be bled to purge the air.
I may be wrong but, the engine in my Ford (A PowerStroke) uses high pressure to deliver the fuel to the engine and a low pressure return line back to the tank. When the truck ran out of diesel (in steps the wife), my concerns were the same as yours. A quick phone call to the trusty diesel mechanic who promptly told me in non-engineering terms, “Put diesel in it and it will fricken start. I promise” proved me wrong. Why? I do not know exactly, but it did.
I know the return line is common place on all fuel systems. I do not know if this diesel engine has a special system to prevent vapor lock.
One concern I do have about a diesel engine in a plane is what happens if the engine does quit? Does the prop windmill?? Given the higher compression ratio of a diesel engine, would the airflow past the prop be able to turn the engine over, therefor reducing drag in a engine out scenario? Or would the prop take a 12 and 6 position and stay put?
.
Well, I’m only going on what I’ve been told - and I used to have a diesel generator that had exactly this problem - run it dry and it would not go until the injection line (single cylinder) was bled.
I do not know if a single cylinder diesel engine on a generator can be compared to a truck or airplane engine. All I can say is that if you run out of diesel in a PowerStroke Ford, it will restart. I would be interested to know the year of the generator.
If it did stay put, that would be good - a windmilling prop has more drag than a stationary one.
I have a question concerning the drag of a stationary prop. Is there an airspeed where drag is reduced by a revolving prop? As the airspeed decreases, is there a point where a stationary prop has less drag than a revolving prop? Or is a stationary prop going to ALWAYS have less drag than a revolving prop…I do not know but would be interested to get an answer.
Thanks Bob #509
.
I have a question concerning the drag of a stationary prop. Is there an airspeed where drag is reduced by a revolving prop? As the airspeed decreases, is there a point where a stationary prop has less drag than a revolving prop? Or is a stationary prop going to ALWAYS have less drag than a revolving prop…I do not know but would be interested to get an answer.
Thanks Bob #509
I won’t pretend to be an expert but I believe I read somewhere that the windmilling prop acts as a “flat disc” in the air; ie its almost like a flat panel sticking out in front if the aircraft. Much less drag is encountered with the prop still.
I agree.
You have to be very slow, sometimes (depedes on eng size)hold it in a stall to get the eng to stop, once stopped you can gain plenty of speed before it will move again. While stopped you have a better glide ratio then when it is rotating. Come to VA I will give demos on your aircraft, on the house, for Cirrus wanta-bees and the lucky ones that already have one only, others will be billed for Pilot Services (CFII). Have a great Cirrus day.
Woor
ATP CFII A&P
I have a question concerning the drag of a stationary prop. Is there an airspeed where drag is reduced by a revolving prop? As the airspeed decreases, is there a point where a stationary prop has less drag than a revolving prop? Or is a stationary prop going to ALWAYS have less drag than a revolving prop…I do not know but would be interested to get an answer.
Thanks Bob #509
I won’t pretend to be an expert but I believe I read somewhere that the windmilling prop acts as a “flat disc” in the air; ie its almost like a flat panel sticking out in front if the aircraft. Much less drag is encountered with the prop still.
… but CD resp. General-Enterprises accepts already $30K downpayments… so first-come first-serve!
My mistake - re-reading the announcement, they do say they are taking reservations. Which is not the same as signing contracts. What happened with the SR22 as I recall is that when the specs were frozen and delivery dates available, the refundable deposits were converted to non-refundable contracts, and existing SR20 position-holders were offered a chance to switch. So I would expect something similar to happen here. But I guess we will have to wait and see.
I spoke to Cirrus today about converting my SR22 position to an SR21tdi and was told that it would probably be a straight swap with approximaely the same delivery date.
This is not a definite yet and I will need to wait and see the price and performance figures.
And before you ask yes I do live in Europe
Simon
Did they also quote you a price for the TDI ?
Jaap
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Did they also quote you a price for the TDI ?
Jaap
The person I spoke to said that there would be no figures available (price and performance) for about 2 months.
She confirmed that if I wait until then, rather than swapping now, that it is my current position number (179) that will count not when I choose to swap with regards to the eventual delivery date of the SR21.
In short I will not be penalised if I wait.
Simon