testwest

I haven't heard from Mike at Hartzell regarding the BA props. KSMooniac had a McCauley in his hangar, think it is the same one as you. Hopefully he can measure his blades and come up with the smae number. The spreadsheet uses a standard numerical integration technique for the computation, but there are a few non-obvious items that need to be done to get the numbers, such as hitting F9 after entering the prop diameter to compute the correct stations for that diameter. Did you look at the 2-blade Hartzell with the 7666 blades already modeled on the benchmark site? The BAF for that should be similar. BTW, thanks for the effort!

Anyone have this STC and can comment on performance? Thanks!

I hope Aveo Engineering can finally get the Galactica series (TSO'ed) in series production. For more information, look here: http://www.aveoengineering.com/Aviation/Airplane_LED_Lights/index.php They have been touting the certified lights for a year, make lots of uncertified lights for LSAs and Experimentals, but my guess is that they are finding that there is a reason so few manufacturers make TSO'ed or PMA'ed stuff....the regulatory burden is a mite high. We are planning to install a pair of "Ultra Embedded" Galactica lights in the tips, and a "PosiStrobe CP" in the tail of our J, and will have a complete working Hoskins system for sale when that happens.

Yep, that's it, just the blade width. The thickness only matters at the tip, and then only if the tip is transonic. The back side of the older props is flat, so there are not any significant airfoil differences among the certificated props....except for the scimitars. I think the calculation of the BAF is more complex for the newer blended-airfoil (BA, or "scimitar") props than for the traditional designs. I have written Mike Trudeau at Hartzell for info on the BA series. Will let you know.

Lopresti Aviation is picking up on the Benchmark activity, we are starting a "thing"...here is a letter from him to Alfred Scott, the author of Benchmark: Alfred I helped develop the installed power chart for the original 201 in 75 or 76. The data we used to develop the chart was based on in flight torque meter data which we felt was very good. I haven't seen the folder with that data for many years. After Roy pas[sed] we cataloged a lot [of] the data he had collected in 50 years or so. There are boxes and boxes of the stuff. I keep telling my self that when things slow down I will go through it, but as you have probably guessed things never slow down. I am in the middle of a IO-360 project now. We are developing a new cowling for the Cessna 177RG. I am also installing a DeltHawk diesel in a Cirrus SR20. I would like to use BenchMark for the flight test programs on both of these jobs. How do I get a current copy? Thanks Curt Curt LoPresti President, LoPresti Aviation Now what would really be cool would be to input the original, raw drag polar flight test data from 1975 into Benchmark!

Right on, my friend. Let me know if you have any trouble with the spreadsheet.

OK, here is where we are so far: Magnus: Produced the IO-360-A, C, D series angle valve Lyc engine model, it is already on the Benchmark site, here: http://www.seqair.com/benchmark/index.html#benchmark Prop activity factor volunteers: Eldon (jezzie) - McCauley B2C34D212 (original J prop, square tips) Magnus - McCauley B2C34D214 (follow-on McCauley prop with rounded tips) Hank - Hartzell three blade Top Prop STC (non-scimitar) HC-C3YR-1RF/F7282 (this is for C-J models, the STC is different due to the different spinner) testwest (me) - Hartzell two blade Top Prop STC (scimitar) HC-C2YR-1BFP/F7497 (this covers A-G and J models) J Props for which we still need a blade activity factor (BAF): MT Propeller MTV-12 (KSMooniac?) Hartzell 2 blade non scimitar Q-tip HC-C2YK-1BF/F7666A-3Q (anyone have one of these?) Other props for other models? Awful_Charlie, are you in? As a reminder, the procedure for measuring your prop and a downloadable spreadsheet that computes the BAF are located here: http://www.avweb.com/news/airman/182418-1.html After you enter the prop radius (not diameter), number of blades and clear the station widths, hit F9 to recaculate the station distances, then print the sheet for measuring. Hank, check your e-mail for the files. Also, if you are doing the measuring with the masking tape and marks per the above, get some pictures of you doing the measuring! I have an idea for an article for MAPA or AOPA, tentatively called "Flight Test in the iCloud". Thanks again everyone.

Ok, that should not be an issue as we can make measurements on an actual prop blade and compute the BAF using the spreadsheet I referred to earlier in this thread. Thanks for making the effort, Magnus! KSMooniac has an MTV-12 on his J, Scott would you be willing to help? Magnus has a C214, I am going to write Hartzell for the BA prop info (or take measurements), we need someone to step up that has the older square-tip McCauley and also someone who has a 3-blade Hartzell. Any volunteers? No flying needed, just some precise measurements on your prop and the ability to put those measurements into a pre-done spreadsheet. As a reminder, the procedure and downloadable spreadsheet are here: http://www.avweb.com/news/airman/182418-1.html Thanks, everyone!

Here is a nifty owner web site for a Turbo F, the referenced page has a large chart of performance data: http://www.cnrepperson.com/flying/9791m/9791m-enginePerformance.htm At FL200, DA218, 25 squared, they get 121 KIAS, 171 KTAS. No mention of fuel flow, though. KSMooniac, +1. We are getting ready to upgrade our J to an EDM-930 from a -700, and Scott is right on that as well, all the probes can get re-used. It is a nice upgrade path.

Hi Mike Sorry, I did not know you had the C320 (Cessna Skyknight, right?) time. Was it your own airplane, or flown for an operator? I try to make my posts helpful for the recipient as well as maybe giving some info to third parties who are here to visit and learn, did not mean to "give you a lesson", as it were. Having said that, depending on the C320 model, the engines were either Continental TSIO-470x or TSIO-520x. Both were low-compression engines with certificated cooling margins under boost. Your F, unless it has an intercooler, is a bit of a different animal. Even though the TN boost may not be nearly the amount of boost as a turbocharged low compression engine, the intake charge can get pretty hot. Notice again on the graph I posted the CDT of almost 175 degF. So in your case, with no intercooler, you could be feeding 150 degF+ air to an 8.7:1 engine, versus the 7:1 or 7.5:1 of the Skyknight. I'll gently suggest, one more time, as owner-operator who is on the hook to pay the maintenance bills, to consider the engine analyzer as a top priority. I have personally saved significant maintenance money on at least 10 events with various airplanes with analyzers, and had my butt saved twice. Hope this helps!

A stalled centrifugal flow compressor can still provide a "slight" boost above ambient MP, the flow is still in the normal direction, it's just...crappy, for lack of a better word. A sudden drop of MP to above ambient pressure, happening rght after some reduction in exhaust flow or increase in demanded MP, is likely a compressor stall. If undoing what you just did makes the MP come back, that's it. A sudden drop of MP to ambient pressure, however, is a serious emergency. That is likely a broken exhaust pipe, and an engine fire may quickly ensue. Throttle idle and look for a place to land. Shutdown the engine, fuel pump and close the fuel valve if there are any other bad indications. From turbo altltudes above most places in the US you have lots of landing options. Use a) your glider rating and your recent practice in a simulated forced landing scenario to assure a survivable outcome. If you are c) none of the above, there are some more things on your gift list!!!

Hi M20f (RL name is?) For the next major holiday in which you expect to receive gifts, ask for a JPI 830 engine monitor. Add on fuel flow and compressor discharge temeprature (and IAT if you have an intercooler). Then, learn what the supplied information means. Your engine and wallet will thank you.

You might have experienced a compressor stall. This can happen if the mass flow through the turbine is insufficient to maintain the demanded pressure ratio across the compressor. Attached is a JPI data dump from a compressor stall in a TN IO-540-S1A5. Other than two extra cylinders, it is basically the same engine as yours (e.g. angle valve Lycoming, TN, ~50hp/cylinder). If the rest of the turbo system is operating normally, you may just have a not-so-great match of the turbo map with those conditions. A little more RPM will be OK, but if it is really cold and you see a slow down while adding a lot more RPM, you are starting to see some transonic losses at the prop tips. Doesn't hurt anything, but is annoying. Also, that fuel flow seems awfully high. Again, looking at the attached picture, at the right side I got the engine settled at 26"/2300 RPM after recovering from the stall (by adding back the RPM, just like you did). The fuel burn is about 16 gph from the graph, ROP, 26"/2300 and ~70%ish power on this engine....but it is a 290 hp six-cylinder.

Congrats to Magnus for producing the first Benchmork model for the Mooney, it is an IO-360 engine model that reflects the POH power settings. Well done!

I'll definitely check on that, thanks Magnum. BTW, I do have the memory stick with all the J tech data from Mooney, which means I have the entire range of POHs.

Once you have developed either a prop or airframe model in Benchmark, we can share the files on the Benchmark site, here: http://www.seqair.com/benchmark/index.html#benchmark Just e-mail the files to Alfred Scott at Sequoia and he'll post them on the site. You will find several models already posted. What propeller do you have? My top priority right now is to get a blade activity factor number for a McCauley B2C34D212 and D214 prop. Hopefully someone will volunteer to email McCauley and get that. I have a Hartzell BA that will have a different BAF. Failing that, it is possible to measure a prop and compute BAF with a simple spreadsheet. The procedure and downloadable spreadsheet is here: http://www.avweb.com/news/airman/182418-1.html Thanks for your interest, Magnum!

I have that one, it is quite good. However, Benchmark goes far beyond in being able to model any engine, but right now there is not an LOP model in Benchmark....which really should be a breeze since the hp is a straight function of fuel flow (15.1 * FF = hp for 8.7:1 CR). Workin' on that. In the meantime, are there any Mac guys willing to download Benchmark and start plugging their M20 POHs into the program for their particular airplane?

Hi everyone: For background, read this thread: http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=1&threadid=3273 The Falco guys are way ahead of everyone on modeling their airplanes in Benchmark. One of the builders has produced the attached gem. He does have a couple of "nits"..he has a notation for no "oversquare" ops for greater than 75% power, and throttles the engine between 75% and 65% instead of WOT. Below 65% he does show WOT, but "economy" operation (not LOP). But the cool thing is this no-wind optimum cruise RPM range. He shows 8000', WOT, 65% power, 2200 rpm. Result is 168 KTAS on 8 gph. My guess is that he has a 180hp parallel valve engine. This type of cruise chart, adjusted in real time for cruise winds, would be a really nifty app for us Mooney drivers. We do need to create the model for Benchmark. Any Mac guys out there?

We did the same thing on our J model. MSC cert not required. The part number is assigned to the type certificate, should require no more than an IA sign off. Take a look at our gallery here: http://www.mooneyspace.com/index.cfm?action=gallery&userGallery=412 The modified-to-smooth-belly shot is right in the middle of the page.

Lone Star used to have a set of overlapping doors in stock....

Where are you getting the work done? And +1 for the tail group...check over at Lone Star Aero for the parts too, at San Antonio Int; Airport. Dennis Bernhard is the man there.

You are welcome, sir!

And some notes on the MPG chart: "Now that you have entered all of the data, analyzed all of the curves, you are ready to produce some aircraft performance charts. The most important of these—and the raison d’être of Benchmark—is the miles-per-gallon chart. The miles-per-gallon chart concept was originally developed for the B-29 bomber. With that aircraft, it was imperative that the flight engineer operate the aircraft for the greatest practical efficiency, which was no easy task when you considered the large changes in aircraft weight, as well as other variables like winds and altitudes. In fact, on the B-29, the flight engineer was supplied with charts that showed the most efficient power settings for four-, three- and twoengine operation. These charts are extremely useful since they tell you at a glance for a given altitude which are the most efficient power settings to use, how fast an aircraft will fly at various weights, the miles-per-gallon efficiency of the aircraft, and a temperature correction chart for non-standard days. These charts were first introduced for general aviation aircraft by Mooney Aircraft in the early 1980s and proved to be very popular with efficiency-conscious Mooney 201 pilots. The development of these charts was done with largely manual methods, using a series of look-up charts for this mathematically rigorous approach. In a few hours with Benchmark, you can duplicate the work that Mooney spent about $25,000.00 to accomplish—and with greater accuracy." [emphasis added] [from http://www.seqair.com/benchmark/BenchmarkManual.pdf , page 42]

This is the airspeed calculator output on Benchmark.

Thanks again, everyone. I know this is a really technical subject. For JimR, the actual derivation of the full CAFE formula: V**1.3 x MPG x Wp**0.6 (where Wp is payload (not fuel or oil) weight, to a maximum of 200 lb per certificated seat) is partly analytical and partly empirical. The PAV paper I referenced at the beginning of the thread goes through the entire process, it is excellent. If you can't get at it, I'll email you a copy. It does favor speed somewhat, but the original CAFE formula V x MPG x Wp wound up restating Carson's Speed in a parallel effort in 1980. And Carson's Speed as a cruise speed has never gained any traction in GA, because the required power level of ~50% is just too slow for most owner-operators...BSFC is lower at that power setting, too. For fantom, welcome! You are never late. And yes, there is a checklist for data. I am working on making the test card "Mooney Friendly"...there is a little homework, though. Probably the first thing would be an accurate and recent weight and balance. There are several W&B spreadsheets floating around on the site here....