Sopwith Baby Project - Page 54

mark_pilkington · 18 November 2008, 05:19 PM

Quote:

Thanks for your insight Mark. I think we have talked on the phone - by my notes about 6 years ago! If you are the same person I was thinking of - regarding Wackett drawings?

The Rotec engines are certainly nice engines. I just don't think the R3600 has the grunt. It works well on the aluminium structured 100% replicas but can't swing as a big a prop as some claim. I need something that can give me the low RPM with the big (100") prop. If you disagree, please let me know. I'm keen to resolve the engine issue for my own project which is why I', so interested in Joe's design decisions. Very helpful thread

Brisfitworks has previously suggested the M14 225hp example is an option given it's tolerance of low RPM and propensity for swinging big props. His calculations were convincing (just have to find them again!). My only trouble with this engine is the space needed behind the engine is significant. I think it would end up with engine components on my lap in the Ni17! I plan to draw up the fuselage in CAD and test fit the engine and components....all on my long to-do list....

Yes, I think we have discussed Wackett Trainer drawings, in regards to the Rotec 3600 I have'nt undertaken a power rpm analysis and cant comment on its suitability for your particular application, but it would certainly seem suitable for aricraft currently using 120 or 140 Warners?

The Jacobs R755 at 220HP would be my own next choice given its ready supply in zero time overhauled condition from the US, and readily acquired spares, it is a larger diameter engine perhaps creating a problem for some replicas, and that was one concern when considering it as an alternative engine when first pursuing my Wackett restoration, luckily I now hold enough Warner 165 parts to be self sufficient for my own needs.

I cant comment on the M14, but it does seem to be a reliable and good engine?

The M14 apparantly has a diameter of 984mm so it is narrower than the Jacobs which is 1118mm , and is shorter at 920mm in length, as compared to the 1020mm of the Jacobs, so if length is a problem for you the Jacobs will be worse.

Another readily available US engine is the 7 cylinder Continental W-670 of 220HP, its is an even larger diameter to the Jacobs at 1080mm, but is a shorter engine of 869mm length?

Probably the "best" Scarab equivalent engine in the 160HP range is the Kinner R-55 or R 540, which is only 5 cylinders with 160HP at 1850RPM, with a diameter of 947mm and length of 775mm, as compared to the 7 cylinder Warner 165D with 7 cylinders of 165HP at 2250 RPM, with a diameter of 1153mm and length of 853mm (note I incorrectly converted an imperial diameter in my post above for the warner - quoting a 902mm diameter in error).

However I have no idea of the cost and availability of the Kinner R5/55/540 engines and suspect they are not as available as the Jacobs but perhaps more available than, or same as, the Warner these days?

Is your friend interested in parting with his "boat anchor" Warner Scarab?, as I continue to seek spares.

regards

Mark Pilkington

Joe Perkel · 19 November 2008, 03:07 AM

Quote:

Originally Posted by Nick

Hi Joe,
Good to see some progress there.
Just reading the book on Tom Sopwith “Pure Luck” at the moment. It mentions that when they were expanding the factory as soon as the floor was laid, work benches would appear and carpenters & metal fitters would start work . The walls were erected around them. Maybe you could do the same.

Cheers, Nick

Nick,

I just ordered that biography, thank you for mentioning it. I have been quite fascinated with the corporate culture Sopwith seems to have created during this war.

Interesting title, I wonder if it eludes to "Pure Luck" from a business standpoint, "Right place at the right time", kind of luck?

One can mentally imagine the kind of production desperation indicated by the scene you describe! Looking forward to reading it!

As for my own "production desperation", I just simply have to try to cool my heels. I'm really pissed at the contractor, but I've got him by contract now for monthly liquidated damages. Still, even with that, we've slowed to a snails pace again, due to subs holding things up!

Joe Perkel · 19 November 2008, 03:20 AM

Mark,

Very nice summary on these engines. Very informative, thank you!

brinesharks · 19 November 2008, 11:02 PM

Quote:

Originally Posted by mark_pilkington

Another readily available US engine is the 7 cylinder Continental W-670 of 220HP, its is an even larger diameter to the Jacobs at 1080mm, but is a shorter engine of 869mm length?

Probably the "best" Scarab equivalent engine in the 160HP range is the Kinner R-55 or R 540, which is only 5 cylinders with 160HP at 1850RPM, with a diameter of 947mm and length of 775mm, as compared to the 7 cylinder Warner 165D with 7 cylinders of 165HP at 2250 RPM, with a diameter of 1153mm and length of 853mm (note I incorrectly converted an imperial diameter in my post above for the warner - quoting a 902mm diameter in error).

However I have no idea of the cost and availability of the Kinner R5/55/540 engines and suspect they are not as available as the Jacobs but perhaps more available than, or same as, the Warner these days?

Is your friend interested in parting with his "boat anchor" Warner Scarab?, as I continue to seek spares.

regards

Mark Pilkington

Thanks for your notes Mark - on the W670, Nick is using one in his Snipe. The larger airframe makes it a sensible engine option and should fly it nicely.

I think you are on to something with the Kinner. Walt Refern used one in his N17/24 replica. If it could pull around the heavier steel tube version it could easily pull around the original airframe (minus war load!).

Alas I have been trying to convince my friend to part with the Warner without success. He also has a Jacobs (not sure of the model). He seems a little reluctant these days. If you had some P40 or CAC Mustang parts he would probably talk to you! I actually went trekking through the QLD bush for P40 parts in an effort to get some parts to swap. Only found Boomerang parts! I donated them to a project that's now flying - so a good result.

I might look into the Kinner - however the Aussie dollar is so sad at the moment I might hold off. I might look locally if there are any about.

Sorry to hijack your thread Joe - but I think our engine requirements are almost identical!

Joe Perkel · 20 November 2008, 03:06 AM

Quote:

Originally Posted by brinesharks

Sorry to hijack your thread Joe - but I think our engine requirements are almost identical!

They are indeed! No hijack possible,..very productive!

Maxim08 · 20 November 2008, 07:11 AM

brinesharks,
I've been looking for a Kinner for a few years now for a DH2 project. By comparison, Warners are a 'dime a dozen'.
Regards,
John

Joe Perkel · 28 November 2008, 10:12 AM

Quote:

Originally Posted by Maxim08

brinesharks,
I've been looking for a Kinner for a few years now for a DH2 project. By comparison, Warners are a 'dime a dozen'.
Regards,
John

John,

I've been meaning to address this post for awhile. The DH2 is a truly unique and very interesting aircraft. Few of the mostly conventional biplane types from the era display the "WWI Looks" that these do. I even ordered the Redfern drawings, (not much there).

I calculate about 75 ft lbs short of original torque using the larger Rotec R3600. There seems to be one or two pushers on the Rotec site, I assume the thrust bearing is acceptable as a result.

The original's empty weight was 947 lbs,..is that right?

Would love to see more of these, it looks like a nice follow-up project for later years.

Joe Perkel · 8 December 2008, 02:34 PM

My level of frustration is immeasurable as I await this bonehead of a contractor to finish my house! In the meantime, I'm in such tight quarters that I cannot even roll out my drawings to do CAD work. So planning my workspace seems a good option for the moment.

This small space is one of the deciding factors in pursuing the plane as original. Easier to manufacture, crate, and store all these small components, (including fuselage) for later assembly. As you can see, I've decided on a general layout.

What I could use advise on, is considering the available work surfaces and floor space, aside from the usual hand tools, what would you guys suggest as "required equipment"?

I've come up with the following.

1- Quality Benchtop Belt Sander (Nick's #1 suggestion)

2- Free standing Bandsaw, (or benchtop?)

3- Free standing Router Table, (or benchtop?)

4- Vise

5- Dust collection system

Any advise on the above, (brands and or sizing), and other items that should be considered, would be greatly appreciated.

Leatherhead · 8 December 2008, 02:43 PM

I'd add a compressor and grinder/polisher

Joe Perkel · 8 December 2008, 04:17 PM

Quote:

Originally Posted by Leatherhead

I'd add a compressor and grinder/polisher

I already have an electric benchtop grinder/polisher, and I suppose some space under the table for a small pancake compressor for some limited sheet metal work (hand cutters maybe). I can see a use maybe on the cowl pieces eventually, but have to measure the exits.

This brings up a question. How do you spot burnish the sheet metal on these cowls?

Must be a fast rotating hand tool,...Likely a use here for the compressor then.