SonexBuilders.net

Hi guys and gals I am new to the forum and scratch building a legacy sonex. I am considering a hummel 2400 from scott casler I have seen a few on youtube and wonder if anyone has any experience with this engine airframe combo. Specifically the performance data I.E. the climb rate/fuel burn/cruise speed and comparison between other vw based engines. thanks in advance for any info. Scott

Hey Scott,
The Hummel engine is a minority here but not unheard of.
search.php?keywords=Hummel+2400

Welcome to the forums!

My engine is very similar to the Hummel 2.4L.
The biggest difference is my dual magneto at the back, the standard Hummel has a single magneto and gets it's secondary igntion (if you choose to have one) from the distributer.
The Nickasyl cylinders, bore, stroke, cam etc. are all std. Hummel.
Anyway, performance should be quite similar.

Here's a ink to my phase 1 test report you can download, you should find lots of performance data in there:
https://www.dropbox.com/s/628avhi0vc19m ... t.pdf?dl=0

Also here's a video of my first flight:
https://www.youtube.com/watch?v=VKGuEdH9Fcs&t=250s
I don't have a VSI but you can just count 30 seconds from when I start climbing (3:45 - 4:15) and look at the altimeter difference.

And here's a video of me pushing the throttle wide open,
https://www.youtube.com/watch?v=tqVj2IJEbHI
I start off cruizing at 120KT, I push the throttle open and not long after you can see the speed creep towards the 150KT mark
I did not let it go to its maximum speed as the EGT warning started going offwhich you can see as well on my E1 instrument.

(EGT's are my biggest problem BTW with this engine, CHT's never get anywhere near their limits)

rizzz wrote:(EGT's are my biggest problem BTW with this engine, CHT's never get anywhere near their limits)

How did you determine EGTs to be a problem? My understanding of EGTs is largely influenced by some writings by Mike Busch like: http://www.gami.com/articles/egt_myths.pdf

I'd expect that as long as your CHTs are fine and the engine is running smooth with no detonation that the measured EGT value isn't significant as it is influenced by a lot of variables such as sensor placement, engine RPM, etc. I readily admit that there is a lot of hand-waving in this statement i.e., how do you really know how much margin you have from detonation?

gammaxy wrote:

rizzz wrote:(EGT's are my biggest problem BTW with this engine, CHT's never get anywhere near their limits)

How did you determine EGTs to be a problem? My understanding of EGTs is largely influenced by some writings by Mike Busch like: http://www.gami.com/articles/egt_myths.pdf

I'd expect that as long as your CHTs are fine and the engine is running smooth with no detonation that the measured EGT value isn't significant as it is influenced by a lot of variables such as sensor placement, engine RPM, etc. I readily admit that there is a lot of hand-waving in this statement i.e., how do you really know how much margin you have from detonation?

Interesting.

My EGTs can go over 760 degrees C (1400 F) quite quickly if I don’t control my climb, this is the limit I set on my EGT warning based on various VW sources.
I have never seen CHT’s over 205 degrees C (400 F).

I have the sensor on the rear exhausts pretty close to the cylinder, I do have my exhaust wrapped which might be a contributing factor?

Thanks rizzz I have seen all your youtube videos and that is a very nice sonex and part of the reason I posted the question. I don't see a lot of published info regarding the performance and fuel burn of the hummel so I thought this would be a good place for info. Thanks to all that respond.

Can't speak of the engine performance but the guys that run Hummel are stand up guys. They put my sonex up in their hanger for two nights and loaned me a car when I got stuck in Ohio due to weather on my way to Oshkosh two years ago.

Keith
#554

hollandvw wrote:Hi guys and gals I am new to the forum and scratch building a legacy sonex. I am considering a hummel 2400 from scott casler I have seen a few on youtube and wonder if anyone has any experience with this engine airframe combo. Specifically the performance data I.E. the climb rate/fuel burn/cruise speed and comparison between other vw based engines. thanks in advance for any info. Scott

Hi Scott.
I believe what you are asking will result in subjective responses .
Fuel burn will vary from engine to engine of the same make based on mixture settings ,RPM etc. In the end they all burn between 4 and 4.5 Gal/hr wether Aerovee ,Hummel or Great Plains.Choosing which engine to buy was a long process for me as I studied them all extensively and made a lot of phone calls to Hummel Great Plains and Remaster.

I chose the Hummel for three reasons.One ,it comes already built,balanced and tested .Two the price was less than the Aerovee and Revmaster ,and three Scott Casler who I talked with several times on the phone and at Oshkosh convinced me he was extremely knowledgable .I liked him and decided to buy the Hummel knowing full well that I would be on my own .In the end Scott was a great help and guided me when I had concerns .

If you don't mind building your own engine then get the Aerovee .You will have the benefit of excellent Sonex tech support and everything will fit as designed.It's a very nice package.I just didn't want to build my own engine and my reasons are my own.
Good luck in your decision .Which ever engine you choose it will be the right choice for you.
Mike

Mike I agree it is a tricky question with many different variables but the aerovee has been well documented and I just wanted an idea of the hummel data for comparison. I have decided to go hummel since I knew scott was a real stand up guy and his engines use the front bearing designed by steve bennet and it is very robust. Plus with scott you can build your own or have him assemble and run it. I will be building my own and feel comfortable after building 50 or so vws over the last 20 years. Thanks for the input Scott

Hi Scott,
I have the Hummel 2400 that was built by Scott. I only have 15 hours on it so I can't give great numbers yet but I have talked to Scott multiple times and email him multiple times also. He is always very prompt in getting back to me and very professional. So far I am pleased with my choice. I chose the Hummel for the same reasons, already built, I like the prop hub and the price. Good Luck Densil