enginehistory.org

[jschauer]

Thanks for the lead, it's a bit pricey, but I'll keep an eye out for a deal on Alibris.

[klankenau]

In the mid-nineteen thirties, the airships Akron and Macon used water recovery apparatus attached to their engines exhaust. In this specific application, the intent was to collect water as ballast to offset the fuel consumed during engine operations.

If this method hadn't been used, they would've been required to vent helium as fuel was consumed, limiting their endurance. At this time, helium was considered a strategic material. The US had a virtual monopoly and it was very expensive.

The weight and drag associated with the water recovery apparatus was significant, but deemed worthwhile in light of range and operating cost considerations.

[jjuutinen]

Thanks Kip! By the way, even without water recovery system, cruyising with ADI would make sense: let´s assume that the ADI would save 15% fuel. Assume a fleet of aircraft operating from an island base far, far away. That is 15% less fuel that needs to supplied there as the ADI tank can be filled with sea water.

[jschauer]

Here's an update from the "Warbirds Information Exchange" forum.
Sorry for the late response to all the previous engine questions regarding FIFI, but here's a slightly more detailed version of what is planned...

The new engines will be a combination of two of the latest (and most reliable) 3350's. The engines will have (basic description here) the power section, blower section, and accessory section from the -26WD (Skyraider engine), and have the rotating assembly, nosecase, and cylinders from the -95W (from an AC-119 Gunship). This engine will essentially be a Rare Bear "Light" engine. It is built for 3,500 horsepower, but we will only run it at around the 2,400 horsepower range. That will give us 200 hp more per engine, which the airframe should absorb with no problem, but also gives us the luxury of having available horsepower, should we need it in an emergency.

And so far the FAA is VERY happy with our engine project. With the airplane being in Experimental Category, we're really able to do whatever we wish (within reason), but to have them on board is excellent. I've gone over my plans with them and they didn't have a single negative comment to make about it, other than asking why this hadn't been done sooner.

I'm not certain exactly what we're going to designate the engines as, but they'll likely be called the R-3350-B29, since they'll be custom built just for this airplane.

Anyway, I'm sure there'll be plenty of things we haven't thought of yet, but for over a year an a half, we've been working on this solution, so I'm confident that this is what will keep FIFI flying for years to come.
Thanks for the info Gary. A few questions:

1) Why the combination of 2 different dash numbers for the -3350? It seems like it would be easier to get off the shelf, complete -3350's, instead of having to build a new one each time an engine gets cased.

2) Will this new engine change the external looks of the airplane any? Will the cowlings look any different?

3) I believe you said in a previous post that Ezell and crew are going to be working on it. Is the plan for them to build the engines in B-ridge and transport them to Midland for installation and flight prior to delivery to Addison?

4) What is the expected TBO on these new engines? How does that compare to the current, original B-29 engines?

5) Have you guys decided on a new engine overhauler yet?

Good questions. I'll do my best to answer them...

1. Because there isn't just one engine that will simply fit into the B-29's engine mount and cowlings. The -26WD is the closest, but it's availability is getting more and more scarce (just ask the Skyraider and Sea Fury guys). We already have nine of the -95W engines and wanted to use them due to their strength (built for 3500 hp) so the combination of both engines leaves the hard to find parts of the 26WD to the other operators of that engine and we'll just use the easy to find parts, like the power sections, accessory sections, etc. I truly think this mixture of engines will be the best route to take.

2. NO! The idea is to make it look just like before...only we shouldn't be working on them every time the dang thing shuts down.

3. Nelson and crew are indeed working on it, although they're not actually building the engine. Jeff Abbott is building our first one. Ezell Aviation currently has a nacelle that Kermit Weeks was kind enough to let us borrow and is using that as a mock up for the exhaust and induction systems, among other things. They already have the old -57AM engine removed and have a 26WD mounted to a B-29 engine mount I've given them and should have all of that mounted to the nacelle this week.
The engines, when complete, will be test run at the engine facility, then brought to Midland, where we'll put them on Testiclese (our bad-*ss engine run-up trailer ) and we'll make a QEC out of them. We'll then run them up as a QEC to insure all is well and then install them on the airplane. It may seem like a bit of extra work to some, but it's cheap insurance should something be wrong that we need to resolve.

4. There never really was a "TBO" per say on any of these engines. However, with that being said, we'd like to shoot for a minimum of 1,000 hours on the engines, if not more. Only time will tell. But it's better than between 4-400 hours on the junk that the airplane currently has installed.

5. As mentioned earlier, Abbott Aircraft Services is doing the first engine, and will likely do at least one more for us. We've been in talks with Aircraft Cylinder & Turbine, but they've changed ownership recently and I need to sit down with them and bring everything back up to speed on what our plan is. However, we are NOT committed to just one or two different shops.

Please remember, although not everyone will agree with every single thing we're doing here, we've been trying to think of every possible way to make this work. And I'm confident we're on the right track.

Will it be carbureted or fuel injected?

Carbureted!!! No more of that fuel injection mess. Woo-hoo!!! Now, before everyone starts wondering, "Well I thought it was the carbureted engines that gave B-29's so much trouble..." it was. HOWEVER, the late engines have much better cooling fins and baffles and the injection was not needed as a cooling method, like on the later B-29's. Have you ever heard of a Skyraider having carburetor and overheating issues like the B-29's did? Not likely. So to make things much more simple, we are sticking with carburetors.

[jjuutinen]

If I may, it seems that the injection system used in the R-3350 is/was a poor one compared to the German systems. After all, the Finnish AF which was not the most experienced on more complicated aircraft, managed the injection systems on the Ju 88, Do 17 and Bf 109 very well. Perhaps that is because the German systems were designed from scratch, vs. US system being a bastardized effort to use as many "off the shelf" components as possible. Just take a look at the DB injection pump: a very compact piece that handles all fuel metering requirements. And if need be, you can tune the amount of fuel injected in all individual cylinders.

[jschauer]

Just an update: The Cavanaugh Flight Museum has donated $1.2 million to help us out in exchange for keeping the airplane at his museum during the winter months.

The first engine is in the overhaul shop and is progressing well with some parts ready for paint. We still have a long way to go.