ForcedAeroMotive: SuperCharged DA40

[Antoine]

Brock I am afraid a pic would not help - too many things in foreground.
Let me try again.: I was trying to describe the pushrods that actuate the valve rockers (I think they are called pushrods?)
At the back of the engine case, where the pushrod tube is attached, there is a big gap in the baffling.
But the problem is that it is nearly impossible to fill it without smearing RTV on the metal clip that attaches the CHT sensor to the cylinder head.

Regarding the oil cooler: Well it seems that I am missing a part because I do have PF and the plate on the oil cooler. but no rubber between the plate and the duct. Strangely my oil temps have never been a problem so far. Go figure.

You are of course right about the cover.
I have noticed the presence of the leaks you mentioned, but (excuse my directness) I don't like the idea of fixing the scalloped baffle seal with RTV. There has got to be a way... but I have not found it yet.

[Rich]

Regarding the oil cooler: Well it seems that I am missing a part because I do have PF and the plate on the oil cooler. but no rubber between the plate and the duct. Strangely my oil temps have never been a problem so far. Go figure.

Yes. you are missing part, for whatever reason. There's a "rubber" (or whatever) collar that should be between the oil cooler and the air duct that feeds it.

Maybe the supercharger changes things, but in 12 years of all kinds of seasons all across the US I have only rarely seen oil temperature readings reach 180 degF. Never 190. Mostly 160-ish once warm.

[BRS]

Maybe the supercharger changes things, but in 12 years of all kinds of seasons all across the US I have only rarely seen oil temperature readings reach 180 degF. Never 190. Mostly 160-ish once warm.

We have only seen high oil temps during the climb cool tests (4 qts oil, climb 67 kts w/flaps to 16,400'). No one ever flies this way. Though the SC does change things. Max rated power is reached at about 7100' instead of sea level. So where the normally aspirated plane is making less and less power on it's way to 7K we are making more and more. So yes there will be more heat but it is well managed.

[BRS]

Monday I relocated the project plane from KWJF to KAPA. Since the prior flight (some weeks ago) was a test flight with the supercharger removed (stock configuration) that is how we left it for the flight. Wow, I had forgotten what it was like to fly it normally aspirated. On take-off at 2300' all I got was 26-27" but I had gotten so used to 30". Climbs were slower and as well as cruise speeds. I missed the added utility.

So the plane is in the Denver area now. We have two more tests 'detonation' and 'vibration' then all the testing will be done (unless something needs verification). I won't venture to guess how long this will take as some FAA paperwork is still being done on one of the tests. All this to say, we are moving along. Always slower than I would like but we are making progress non-the-less.

[trepine]

Any updates on this project. I'm in the Rockies and have been patiently watching

[BRS]

Yes Trepine, I guess it's time for an update. Thanks for asking.

The bad news is that we have made very little physical-progress since my Aug 28th post above.
The Good News is that our progress tends to happen in spurts, and it looks like we are about to have one of those.

Here is a bit of detail. On the surface it looks like nothing has changed, or even that we have taken a half-step backwards. Backwards, I say because it was decided that one of our flight tests needed to be repeated in order to clarify (prove) the results. We have been trying to get this test done since the end of November but have been prevented, so far, for one reason or another (weather, surgery, work schedules, etc). Finally it looks like testing will happen this weekend. It's just a short flight test that will probably take under 2 hours. However the plane, as you know, is in Denver but the test needs to be done in the Palm Springs (KPSP) area. Yes it's a bother but that's what we MUST work with. -Ugh

The two ground tests are still undone as well. The delay mostly falls on two accounts. One - we wanted to first get the flight test data, and Second - the negotiation with the FAA is still ongoing for the Detonation test.

The Vibration test-plan is complete and approved. So that can be done any time. It's a rather costly ground test done with lasers and computers. I hope to be on site for this one just for curiosity sake.

The Detonation test has been a struggle. The FAA has not yet signed off on this test plan which means we cannot do the test. The problem is that not all the folks needing to approve the test are engineers and as a result seem (this is my take on things) to be overly cautious and adding multitude orders of complications to what should be a straight forward test at max power/critical altitude. They (the faa) mean well and we are making progress together through discussions, explanations etc. This is what I call hidden-progress (as opposed to physical-progress), so we are progressing. It seems though that this test-plan will be approved soon. But then again, I'm not holding my breath.

Thank you so much for your patience and support. I'll double check with Rod to see if he has anything to add.
-brs

ps. In the meantime (past 2 years), while my DA40 has been obligated, this is what I fly to scratch the aviation itch.

[BRS]

Today's flight re-test was successfully completed. Yea!

I'm told that the new data mimics the original test which is a good thing.
Now all that's left are the detonation and vibration ground tests. The vibration test will be scheduled right away. The detonation test will follow as soon a the FAA and we agree on the test plan.

Once all this is done, it's just a mater of our DER writing up the reports and submitting for the STC.

[trepine]

So just curious. Do you have any stats for say 15,500 or 16,500. Looking to run 2450 rpm both ROP and LOP.

[BRS]

So just curious. Do you have any stats for say 15,500 or 16,500. Looking to run 2450 rpm both ROP and LOP.

Yes we do have info at both those altitudes. Though I don't personally have it so I can't give it to you. It's all with rod. What do you want to know?

I remember cruising at 16,500 LOP at over 160 TAS. I was light though and that was over 18 months ago so I don't remember much else.

[BRS]

Progress continues to be slow however we can see the end of the tunnel. We only have these last two tests (vibration and detonation) to accomplish. The test plan for the detonation test-plan was just approved. The vibration test-plan had been approved long ago. So now we will proceed with these two tests which shouldn't take long (providing we can get special fuel - see below). After that the rest is "just" paperwork. Hopefully we will be able to get through that last hoop smoothly.

Hello everyone,

The FAA did not like our detonation test plan and arranged a teleconference 3 weeks ago which included representatives from the FAA Technical Center in Atlanta. After a brief explanation of how the supercharger system works all objections were dropped. However, a number of small changes were agreed to be added to the test plan. The test plan was revised, and the plan was approved two days ago.

One of those changes is that we must use a custom blended fuel with an octane rating of 99.6 to 101. The technical center says most 100LL from the pump is 103-104 octane. The technical center folks gave us their supplier for fuel and I am attempting to secure a drum for the test.

All the equipment and personnel are assembled for the vibration test and we are only waiting on the FAA to approve the person who can witness the test.

Thanks to everyone. We’re almost there.

Rod