What just happened at Reno?

[Paul Krumrei]

WTH, that is it? WE know more now through the media and people we know than what is on the report.

[Paul Krumrei]

Double Post

[P51Mstg]

Look at it this way... WHAT WE KNEW is official now..... Loss of control, impacted terrain. .....

Mark H

[51fixer]

WTH, that is it? WE know more now through the media and people we know than what is on the report.

Its the Gov.
There won't be official reports along the way until the whole report is done probably.

[lmritger]

Well, that was... uninformative. :-/

The discussion on the recent pages regarding engine builds has been extremely interesting and educational- thanks go to all who've shared that information. Just one technical question- what does ADI stand for?

Also, has there been any update on the two people still listed as missing, or has all that been cleared up now?

Lynn

[JohnTerrell]

ADI stands for "Anti-Detonation Injection".

[Bones]

http://tinyurl.com/3j8gg8l

[mike furline]

http://tinyurl.com/3j8gg8l

Hilarious!

[CAPFlyer]

I'm not sure what exactly you guys were expecting from the preliminary report beyond a confirmation of the basic facts of the accident. That's all any preliminary report gives.

For example (like I posted in the other thread), here's the prelim on the T-6 that went down a few days later -

NTSB Identification: CEN11LA651
14 CFR Part 91: General Aviation
Accident occurred Saturday, September 17, 2011 in Nunica, MI
Aircraft: NORTH AMERICAN AT-6, registration: N217RK
Injuries: 1 Serious.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On September 17, 2011, about 1815 eastern daylight time, a North American AT-6, N217RK, sustained substantial damage when it impacted a tree and terrain after a loss of engine power during takeoff from runway 8 (3,600 feet by 100 feet, dry turf) at the Hat Field Airport (5N7), near Nunica, Michigan. The commercial pilot received serious injuries. The airplane, registered to Tailwinds Inc., was being operated under the provisions of the 14 Code of Federal Regulations Part 91. No flight plan was on file for the personal flight. Visual meteorological conditions prevailed at the time of the accident. The flight was originating at the time of the accident.

The airplane was the fourth airplane in a flight of five to depart 5N7. The airplane lost power during its takeoff, impacted a tree on the left side of the runway, and subsequently impacted terrain. The pilot was taken to a hospital for his injuries.

However, I do think we'll see interim reports because this is classed as a "major investigation" and the NTSB has historically issued interim reports on such accidents to include any flight data recorder and/or video information when it has been fully analyzed.

[b29flteng]

ADI stands for "Anti-Detonation Injection".

Water injection (ADI) has been used in both reciprocating and turbine aircraft engines. When used in a turbine engine, the effects are similar, except that preventing detonation is not the primary goal. Water is normally injected either at the compressor inlet or in the diffuser just before the combustion chambers. Adding water increases the mass being accelerated out of the engine, increasing thrust, but it also serves to cool the turbines. Since temperature is normally the limiting factor in turbine engine performance at low altitudes, the cooling effect allows the engines to be run at a higher RPM with more fuel injected and more thrust created without overheating.[3] The drawback of the system is that injecting water quenches the flame in the combustion chambers somewhat, as there is no way to cool the engine parts without cooling the flame accidentally. This leads to unburned fuel out the exhaust and a characteristic trail of black smoke.

Piston engined petrol military aircraft utilized water injection technology prior to World War II in order to increase takeoff power. This was used so that heavily-laden fighters could take off from shorter runways, climb faster, and quickly reach high altitudes to intercept enemy bomber formations. Some fighter aircraft also used water injection to allow higher boost in short bursts during dogfights. It was also used on some of the heavy piston engined bombers and some of the larger cargo aircraft such as the C-124, C/KC-97, etc.

As a general rule, the fuel mixture is set at fuel rich on an aircraft engine when running it at a high power settings (such as during takeoff). The extra fuel does not burn; its only purpose is to evaporate to absorb heat. This uses up more fuel, and it also decreases the efficiency of the combustion process. By using water injection, the cooling effect of the water allows the fuel mixture to be run leaner at its best-power setting. Many military aircraft engines of the 1940s utilized a pressure carburetor, a type of fuel metering system similar to a throttle body injection system. In a water-injected engine, the pressure carburetor features a mechanical derichment valve which makes the system nearly automatic. When the pilot turns on the water injection pump, water pressure moves the derichment valve to restrict fuel flow to lean the mixture while at the same time mixing the water/methanol fluid in to the system. When the system runs out of fluid the derichment valve shuts and cuts off the water injection system, while enriching the fuel mixture to provide a cooling quench to prevent sudden detonation.

Due to the cooling effect of the water, aircraft engines can run at much higher manifold pressures without detonating, creating more power. This is the primary advantage of a water injection system when used on an aircraft engine.

The extra weight and complexity added by a water injection system was considered worthwhile for military purposes, while it is usually not considered worthwhile for civil use. The one exception is racing aircraft, which are focused on making a tremendous amount of power for a short time; in this case the disadvantages of a water injection system are less important.

The use of water injection in turbine engines has been limited, again, mostly to military aircraft. Many pictures are available of Boeing B-52 takeoffs which clearly show the black smoke emitted by turbine engines running with water injection. For early B-52s, water injection was seen as a vital part of take-off procedures. For later versions of the B-52 as well as later turbine-powered bombers, the problem of taking off heavily loaded from short runways was solved by the availability of more powerful engines that had not been available previously.


ADI utilizes a mixture of 60% Methanol, 39% demineralized Water and 1% soluble Oil.

[RHenry]

Speedy,

You wrote, "...it's been shown that the tube motors can typically handle higher MAP than the intercooler engines."

One thing I forgot to mention is that how either type of engine “handles” manifold pressure is a function of mechanical strength, how well it’s put together and the quality of the parts. Either type done correctly should be equal to the limits of the above boundaries. It was likely a wordsmithing error on your part but I’m guessing you meant how much manifold pressure each design is capable of developing. To that I agree the nod definitely goes to the aftercooler-less engine.
I agree with Paul regarding flame dampening with excessive ADI. It can have detrimental effects beyond that as well.

I have heard, specifically, that the stock intercooler vanes are prone to cracking at extremely high MAP. A function of mechanical strength as you say, but it's easier to repace it altogether with a straight tube rather than engineer a stronger intercooler unit when the intake charge is adequately cooled using ADI alone.

[Speedy]

WTH, that is it? WE know more now through the media and people we know than what is on the report.

It's just the basic preliminary report, Paul. Most prelims are this short and vague. The final report will have a much more in-depth explanation if it can be determined.

[lmritger]

ADI stands for "Anti-Detonation Injection".

Water injection (ADI) has been used in both reciprocating and turbine aircraft engines. When used in a turbine engine, the effects are similar, except that preventing detonation is not the primary goal. Water is normally injected either at the compressor inlet or in the diffuser just before the combustion chambers. Adding water increases the mass being accelerated out of the engine, increasing thrust, but it also serves to cool the turbines. Since temperature is normally the limiting factor in turbine engine performance at low altitudes, the cooling effect allows the engines to be run at a higher RPM with more fuel injected and more thrust created without overheating.[3] The drawback of the system is that injecting water quenches the flame in the combustion chambers somewhat, as there is no way to cool the engine parts without cooling the flame accidentally. This leads to unburned fuel out the exhaust and a characteristic trail of black smoke.

Piston engined petrol military aircraft utilized water injection technology prior to World War II in order to increase takeoff power. This was used so that heavily-laden fighters could take off from shorter runways, climb faster, and quickly reach high altitudes to intercept enemy bomber formations. Some fighter aircraft also used water injection to allow higher boost in short bursts during dogfights. It was also used on some of the heavy piston engined bombers and some of the larger cargo aircraft such as the C-124, C/KC-97, etc.

As a general rule, the fuel mixture is set at fuel rich on an aircraft engine when running it at a high power settings (such as during takeoff). The extra fuel does not burn; its only purpose is to evaporate to absorb heat. This uses up more fuel, and it also decreases the efficiency of the combustion process. By using water injection, the cooling effect of the water allows the fuel mixture to be run leaner at its best-power setting. Many military aircraft engines of the 1940s utilized a pressure carburetor, a type of fuel metering system similar to a throttle body injection system. In a water-injected engine, the pressure carburetor features a mechanical derichment valve which makes the system nearly automatic. When the pilot turns on the water injection pump, water pressure moves the derichment valve to restrict fuel flow to lean the mixture while at the same time mixing the water/methanol fluid in to the system. When the system runs out of fluid the derichment valve shuts and cuts off the water injection system, while enriching the fuel mixture to provide a cooling quench to prevent sudden detonation.

Due to the cooling effect of the water, aircraft engines can run at much higher manifold pressures without detonating, creating more power. This is the primary advantage of a water injection system when used on an aircraft engine.

The extra weight and complexity added by a water injection system was considered worthwhile for military purposes, while it is usually not considered worthwhile for civil use. The one exception is racing aircraft, which are focused on making a tremendous amount of power for a short time; in this case the disadvantages of a water injection system are less important.

The use of water injection in turbine engines has been limited, again, mostly to military aircraft. Many pictures are available of Boeing B-52 takeoffs which clearly show the black smoke emitted by turbine engines running with water injection. For early B-52s, water injection was seen as a vital part of take-off procedures. For later versions of the B-52 as well as later turbine-powered bombers, the problem of taking off heavily loaded from short runways was solved by the availability of more powerful engines that had not been available previously.


ADI utilizes a mixture of 60% Methanol, 39% demineralized Water and 1% soluble Oil.

What a tremendously informative answer... thanks so much for this, John! This describes perfectly the MW50 setup in the later Bf 109s, which I was familiar with... I just didn't recognize the acronym ADI. Thanks to your post, I now understand the technical benefits of the system, both for wartime and racing purposes, and again, I sincerely thank you.

Lynn

[Paul Krumrei]

WTH, that is it? WE know more now through the media and people we know than what is on the report.

It's just the basic preliminary report, Paul. Most prelims are this short and vague. The final report will have a much more in-depth explanation if it can be determined.

I know, I guess with the speed of technology and the internet, people expect more quicker. Point blank, we all lost a hero, a beautiful airplane and wonderful spectators in the end.

[Ploesti]

I think this thread and the other thread on Reno air racing's future has been extremely interesting to me for the simple reason it went from "what happened?" to "sadness at what happened" to "lets discuss maturely and responsibly what happened" to credible experts here on WIX explaining "what they believed happened" to those same credible experts disecting "what probably happened" to a reasonable and respectful conclusion of "what most likely happened" to an extremely informative explanation of the workings of a modern warbird unlimited racer and what "could happen in a mishap" back in a kind of "full circle" to what the future of unlimited warbird air racing could and possibly will be. Congrats to the WIX community. I'm sure all of you who have had a say over the past week can be proud. Anyone who examines this board, no matter if media or investigators will find of most valuable.

But it still hurts to think about last Friday. hope I wasn't too tactless lol