Hatz Biplane Association

Well, I need to confess, despite all the good advice to the contrary, I went ahead and bought a Warner 145 for HC 129. It is a fairly complete engine which is just as it was when last flown in 1964. Before I rebuild it, I would like to determine it's position, and build a mount. Of course I will move it as far back as possible, and am considering a swing out mount for maintenance.

If anyone has any pictures or descriptions of the engine installation on the Mehlin Smith Hatz, I would greatly appreciate it.

Have you talked to Bill Rusk? If not, I would strongly suggest you do. He owned Mehlin's Hatz flew it more than anyone. He's still on this forum and also on the Supercub forum so his contact info is around. No one know the installation better than him. You're going to want to pay a bit more attention to weight and engine position.

He's building a Cub and is chronicling it on the Supercub forum, but on Page 9 of his thread are some shots of him working on the engine:
http://www.supercub.org/forum/showthrea ... -Cub/page9

Also, here are a couple shots I took when I visited Bill in 2010 (sorry for the giant pics):

JD,

Have you started your fuselage? The Warner Hatz's is extended, I believe.

Steve

Thank you so much Doug. That is exactly what I was looking for. I have met Bill who was generous enough to let me fly his Warner powered Hatz. However, I wasn't able to get a look at the engine mounting at the time. These pictures give me some good insight. I still may convert what Mehlin did to a swing out mount.

I couldn't make up my mind between a Warner or a Lycoming as I was starting the fuselage, so I just made it to plans. Now that it is welded, I'll just have to put the engine as far back as possible, and add weight in the tail to compensate for the extra engine and oil weight.

No problem. As mentioned above and in another thread, Mehlin extended the fuselage 8" all of which was behind the rear 'pit. For quite some time Bill thought there was weight added to the tail of the Hatz to compensate for the Warner, but I asked him to confirm this for me one day and come to find out there was NO weight in the tail (not sure how much the extra 8" helped). Mehlin pulled the engine aft as much as he could and built it very light (no electrical system).

I agree with you on the swing out engine mount; I plan on doing the same thing for the Rotec.

Couple more pics:

Congratulations on your ambition to have an actual Warner powered Hatz. I had considerable interest in the same, as I think the grease blowing back on your goggles would be so cool. Due to the complications with the weight and balance (primarily balance) and the fact my fuselage was done I chickened out. (I'm doing the Rotec thing.)

For what its worth: I spoke to Mehlin at the last Brodhead he attended (can't remember if its been 1 or 2 years now????????)
I spoke with him about the extending of his fuselage to balance the Warner and he said he did indeed extend it (seems to me he agreed on the 8" figure I've often heard) but it was more for aesthetics. He said he wanted it to look like an old plane and "not an acro-sport" (nothing against the acro-sport, just quoting Mehlin) or some new biplane. For this reason he stretched it out and the longerons run straight from the aft cockpit station to the tailpost. It does not have the additional bend near the leading edge of the H-Stab. Although I recall him saying it did make things a little tight back there width-wise. I'm actually builing a CB-1 - maybe all the Classics are as he described his in this regard. He said he intentionally made the cockpit openings as small as possible so the ratio of the size of the plane to the size of the cockpit opening would be more like that of a much larger Waco. I think he said he raised the top wing also to make it proportioned more like a larger plane. In regard to the 8" extension of the fuselage I specifically recall him saying he did it primarily for aesthetics and he chose 8" (or whatever length he chose) because "that was the longest that would fit in his workshop". I"m certain I recall him saying that even with that he still had to add a bunch of weight to the back.

If someone has examined the plane and says there's no weight there, and can determine the tailpost, rudder spar, etc. is not filled with lead, then how can that be argued. If it aint there, it aint there.

Either way, I think Mehlin succeeded wonderfully in his attempt to keep the propotions right because his plane was/is majestic in appearance, far beyond simply what the round engine does for it. Not to mention he was just a really great guy who was willing to talk to and help anyone. His enthusiasm for the building of airplanes................. well, he was a neat guy.

One thing we know is that IT CAN BE DONE. If someone is determined to build a Warner powered Hatz it is possible. Since I'm not building a "proven plan" in that I'm not using an O-200 on my CB-1 I can't be certain how the CG will fall out and so opted for the more easily adjusted H-Stab and also put "hard points" in the very aft fuselage so that I have a place to put weight later if I find it necessary without having to weld them in after being covered, or find some other inconvenient way to add weight or build in 2 battery boxes, etc.

Good luck with the Warner, I'm sure we'll all be watching you.

Jackal wrote:I think he said he raised the top wing also to make it proportioned more like a larger plane.

When I visited Bill we checked this out as well. We pulled out the CB-1 plans and a tape measure and 'lo and behold it is built to plans. Top wing height is standard Hatz.

Jackal wrote:If someone has examined the plane and says there's no weight there, and can determine the tailpost, rudder spar, etc. is not filled with lead, then how can that be argued. If it aint there, it aint there.

Yes, Bill confirmed this for me. I couldn't tell you if the weight had been there in the past and removed before Bill bought it or if it was never there to begin with. What I CAN say is that it wasn't there when Bill bought it.

With just a little eyeballing and basic math estimates, it looks like it would take about 15 lb in the tail to make the empty weight CG location exactly the same as shown on the Classic plans. This is just substituting the Warner for the O-320 and adding an oil tank and oil located on the top longhorns behind the firewall.

Of course there are many other variables in each airplane, and it could be the final weight and balance ends up within tolerance without the added weight. I will just have move forward and make adjustments as things come together. This being my first homebuilt, and the engine alone providing plenty of challenge, I will stick to the plans for the most part. It probably won't look quite as period as Mehlins, and I certainly don't have the skills he most likely did.

Here are a couple of pictures of the engine placed at the front of the fuselage.

That is going to look good. Like I said, We'll all be watching.........

Now, thinking back in regard to raising the top wing higher than plans, I think that was something Lorin Wilkinson said he did on the "Snooty Hatz". I do specifically recall Mehlin talking about the small cockpit openings and other stuff.

Sorry for the initial misinformation and good luck.

I assume you are familiar with Harman Dickerson at Fulton, MO airport (FTT), an authority and source on all things Warner?