Author Topic: Sketched up an ME 110 I Beam...Am I on the right path (Read 1711 times)

Dennis Holler · « **on:** August 31, 2011, 09:13:16 PM »

I think I read to many I beam threads

and then took out some of Jack's I beam plans and ah sketched up an ME 110. Used the Stuka wing as a starting point, straightened it out and swept the LE back and decreased the sweep on the TE to sort of match the ME 110. I just carried over the Stuka air foil for now, but could change it if warranted. I then sketched out the 110 side view over the Stuka using it as a reference. I don't know, It kind of looks like an ME 110. I know I would still have lots to figure out and details to settle, but am I on the right track so far?

At 59" span and 39" length would a couple of .25's be enough for it? LOL, That probably depends on how much of a pig it would end up being

I have to be honest, I just eyeballed it with an 8.5X11 3 view I printed and tied to make the proportions seem right to me. I did stretch the nose a little and I wonder if I stretched the cowlings too much or not.

guess maybe some of my questions would be would I keep the same CG point as the plane I started with or do I need to re-determine the CG, bellcrank location, and leadout position. I was thinking the spar would need to be swept as well to work with the I beam.

wwwarbird · « **Reply #1 on:** August 31, 2011, 10:14:26 PM »

Looks pretty good so far, and a really neat choice of airplane. Kudos for making it a glow model too.

There are a LOT of things to consider when scratchbuilding, especially if you want to end up with a worthwhile Stunt Machine. It is very do-able though. Take a lot of time designing and try to think of EVERYTHING, but don't overcomplicate anything. Overcomplex = Heavy. Try to make as many parts as possible serve multiple purposes.

First off, with a twin be careful how far you stick the engines forward, remember you're dealing with twice the weight of everything.

What is the wing area with what you've got on paper right now? The specs above might be just a touch big for .25's, but I feel like you're in the ballpark.

Keep the weight in mind from the first piece of wood you cut all the way until it's ready to fly. Remind yourself of that everytime you step in the shop to work on it. My own design 700 square inch 64" span PBY Catalina is a very capable Stunter even at 80 plus ounces, but at 70 or so it would be a killer airplane. In hindsight I think it could have been done in that range.

As far as the CG goes, don't worry about the previous design. Just work with your chosen airfoil and design the entire plane around it keeping the CG at the airfoils thickest point as your general reference. This will be a very close starting point for everything that follows. Mount the bellcrank pivot as close to that CG point as possible, and have your front leadout exit the wingtip at that same CG point. Definitely use an adjustable leadout guide and install it so that you can still move the front leadout forward about a 1/2" to 3/4" from the aforementioned initial starting point. This will allow a little forward adjustment if necessary, and you'll still have plenty of rearward adjustment. All of this will get you very close right off the bat for those first flights.

Tim Wescott · « **Reply #2 on:** September 01, 2011, 12:44:46 AM »

I would (a) be concerned about the torsional strength of the wing between the engines, as you have a lot more mass that needs to be kept aligned than with a regular stunter, and (b) don't know what the @#$% I'm talking about, because I've never had the chance to grab an I-beam wing and give it a tweak (I've been flying RC for a long time...). An I-beam wing gets all of its torsional stiffness from the covering; I'd be concerned that the thing would be plenty stiff when it's done and finished, but would split the covering to flinders as soon as the engines were run.

So I'd be tempted to make it a D-tube wing between the nacells, with I-beam outboard. Or if I could find one I might use a generous-diameter, thin-wall carbon tube between the nacells to really tie them together and to the fuse, then I-beam outboard of that. If I went that route I'd meditate on Wayne's comment about over-engineering and weight, though.

Build in a weight box in the nose and one in the tail -- I've designed and built a lot of planes in my life, and I very rarely nail the balance on the prototype.

What Wayne said about engine size: unfortunately there's not a lot of choices between 25 and 40, so if you go a bit big on the airframe you're in a world of hurt.

For that matter, what Wayne said about everything else, too.

Bill Little · « **Reply #3 on:** September 01, 2011, 10:46:44 AM »

Looks good from what I can see!

To discuss Tim's concerns about the center section of the wing (very valid point!), I will point out what Jack did to the F-5-F. (according to the plans)

1. all ribs between the engines are 1/4"

2. the wing is sheeted with 1/16th" between the nacelles. (just cut those ribs down to be 1/16th" lower than the LE and TE. very easy to do with I-Beams)

I don't think I would leave the center section "open bay". And make sure you use silk, polyspan, or SGM silkspan for covering. (that part from the King of I-Beamers, Billy Werwage)

Big Bear

Tim Wescott · « **Reply #4 on:** September 01, 2011, 10:53:55 AM »

I'm not sure if the 1/4" ribs are necessary, but the sheeting between the nacelles, if it's tied in nicely with the spar, will make the D-tube structure that I was going on about.

Bill Little · « **Reply #5 on:** September 01, 2011, 11:02:02 AM »

Quote from: Tim Wescott on September 01, 2011, 10:53:55 AM

I'm not sure if the 1/4" ribs are necessary, but the sheeting between the nacelles, if it's tied in nicely with the spar, will make the D-tube structure that I was going on about.

HI Tim,

Don't know about the necessity of the 1/4" ribs, but it would, in some way, add to the strength of the center section compared to either 3/32" or 1/8" (cannot remember what size Jack used off hand) ribs used in the rest of the wing. Either way, sheeting the center section seems like a "must do".

Big bear

Dennis Holler · « **Reply #6 on:** September 01, 2011, 02:32:44 PM »

Yea, I was thinking about what to do between the engines....

also was thinking of taking the weight of a .46 in the stuka nose length and calculating the new twin mount location form the two engines weight moved back to have the same affect as the original set up. maybe move it back a tad to account for the weight of the nose as well..

Is it fair to add 12 or so oz to the Stuka weight to get a target for the 110, with the 12 oz coming form the twin engines? George said his Stuka weighed about 56 or so oz with a Rojett 40 so maybe 65-68 oz would be a reasonable target or does it need to be likely lighter.. I better figure out the loading since I expect it to have about hte same area as the Stuka

Bill Little · « **Reply #7 on:** September 01, 2011, 09:54:17 PM »

HI Dennis,

You would not need to add 12 ounces unless one of your engines weights 12 oz.......... The weight of the Stuka includes one engine. The weight of the engine plus about 2- 3 ozs. would be closer. Also, aim for well under the 65-68 oz. range. With real good wood selection, and drinking Diet Pepsi (Jack's joke) you can actually build a model pretty light. The 65-68 oz. is 11-14 oz. heavier than my USA-1 (700 sq.in) with the ST G.51 RTF.

Big Bear

wwwarbird · « **Reply #8 on:** September 01, 2011, 11:42:26 PM »

In my blurb above I did forget your mentioning of it being an I-beamer. I'd scrap that plan and go 1/4"x1/4" spar D-tube for sure. And yes, sheet the entire center section to just outboard of each engine nacelle. The 1/4" ribs are not necessary at all, you'd just be adding more weight. 1/8" or even 3/32" will be plenty strong with the D-tube and the center sheeting.

If cosmetics are a real concern, and they should be, I also forgot to mention above to add (weight box) provisions for weight balancing fore and aft. You can get pretty close on your CG estimation on a prototype but you will never nail it. On my PBY I spent a ton of time on paper and head scratching before I ever picked up a piece of balsa. All during construction I would have bet anyone it was going to come out a little noseheavy, but it ended up the opposite. In pre-flight bench trimming I ended up with a touch over 1-1/2 ounces of lead in the nose weight compartment. That's where it ended up staying in final trim as well. Other than some of the wood selection, (I went overkill in a few areas) about the only thing I would change if I built another one is that I'd lengthen the nacelles about a 1/2" to get it closer to a naturally happy CG. This would bring it pretty close and give more tank room as well.

Attached is a photo of the nose weight cover on the PBY. Underneath the cover, which is on the bottom of the nose, is a 3/8" I.D.diameter aluminum tube that runs inside the fuse almost to the top of the nose. It is full of lead.

Bill Little · « **Reply #9 on:** September 01, 2011, 11:45:33 PM »

HI Wayne,

Curiosity has the better of me.......... why drop the I-Beam?

Bill

wwwarbird · « **Reply #10 on:** September 01, 2011, 11:53:41 PM »

Bill,

I just think the I-beam is a trickier build and I feel a sheeted D-tube will give a stronger overall center section. That's just my opinion and preference, plus I know it works well. The PBY uses a 1/16" sheeted D-tube with 1/4" spruce spars and 3/32" ribs from tip to tip and I think a gorilla could darn near use it as a surfboard without any trouble.

Dennis Holler · « **Reply #11 on:** September 02, 2011, 05:24:29 AM »

Last night I just kind of sat back and pondered it all a little bit, resisted the urge to scribble further and did some calculations. As it is/was I think it would have been around 500-510 sq inches, should have been about the same as Jack's plan since I kept the root and tip the same and just moved the LE and TE back. If I stretch the span to 66" from the 58" it should be about 625", so that might be a mod I would consider.

Your right, I wasn't thinking straight on the 10 oz

I'm taking all you guy's suggestions to heart, maybe you 'll keep me from making to big a mistakes!!

So maybe I'll set the weight target around 60z and see how that goes.
I think the extra wingspan will look good with the twin engines and the area won't hurt.
I'm not ready to drop the I beam just yet, besides I'd have to face Jack and say, hey I used your stuka plan but dropped the I beam..I can just imagine the ribbing I'd get

Would I gain anything by changing his airfoil shape to that of say an Impact or any other of the current hot ones people use?

Tim Wescott · « **Reply #12 on:** September 02, 2011, 02:19:11 PM »

On the I-beam: nothing, but nothing, looks like an I-beam wing. If you're willing to go to the effort do do it, making the outboard sections I-beam is going to get you that aesthetic.

I think you need a tube of some sort between the nacelles. Whether you use a big carbon fiber tube to tie the nacelles together and do a fully ribbed wing on top for the aesthetics, or if you sheet the leading edge with ribs behind and I-beam outboard, or if you just sheet the whole center section -- once you've made sure you have enough strength, that's largely an aesthetic decision.

I think I-beam wings look cool. Once I get to the point where I'm not crashing all the time I'll have to build one. So I can fully understand your desire to do an I-beam wing.

On the other hand, a nice jig-built D-tube wing is going to be a lot easier...

wwwarbird · « **Reply #13 on:** September 02, 2011, 09:54:39 PM »

Quote from: Dennis Holler on September 02, 2011, 05:24:29 AM

I'm not ready to drop the I beam just yet, besides I'd have to face Jack and say, hey I used your stuka plan but dropped the I beam..I can just imagine the ribbing I'd get

Would I gain anything by changing his airfoil shape to that of say an Impact or any other of the current hot ones people use?

Dennis,

Another ten cents worth here...

If you want to end up with a good performing Stunter you'll need to remember all the way through that you are describing a scratchbuilt and designed model with this project. With the utmost respect to Jack, (he is one of the greats, no doubt), you would be very wise to push any of the Stuka adaptation thoughts aside and focus on the airplane you want to build. The Stuka, model or full scale, is just not enough like an ME 110 to truly aid you in designing a good performing Messerschmitt 110. Definitely use various proven model designs for your reference and ideas as you go, but for your (original) model start with a clean sheet of paper and try to design your airplane for best performance.

Air Ministry . · « **Reply #14 on:** September 03, 2011, 02:17:33 AM »

Tiss wonderous , ive spent 5.000 years looking at Me 110s for stunt .Theres a Gloster Twin ' shragemusic ' fighter near the same , but fastback & Lanc. like cowls if V-12s. . . anyway . . .

Looks good , Id tend to run a piece of 1/2 x 1/4 @ 30 deg along under the top block to get the canopy frame less than full fuse width . ( have a look at a few of sheeks plans ) & either that & the 3/8 triangle to the bottom edge.
to get a near scale cross section .

The Old ' Yard Rule ' trick ( 1/4 x 1 1/4 spruce ) between nacelles to take landing gear , or two seeing its takeing landing gear , engines and suchlike .

The thing can be built near scale , but im off nazi pant jobs. Had the eyetalian airfarce book last week ( Library )
nice black one with I think pale blue fuse band and sfa markings .
Though the Wasps eye , & dark green battle of britian schemes are o.k. ( have a look at sheeks skyrocket
seeing you insist on the Detroit bit.

Templates and fully sheeted'd look more autentic, but a good bump could end its days, the way youve got it
should have a bit of spring or give .

Side mounted engines could be smart .

Built a diesel 110ish thing thousands of years ago , probly my sixth plane. Was like a pommy cartoon .
so much vibration there wasnt much that wast blurred or flapping . So use a Stiff Spar .

Bill Little · « **Reply #15 on:** September 03, 2011, 04:37:18 PM »

Quote from: Tim Wescott on September 02, 2011, 02:19:11 PM

(snip)On the other hand, a nice jig-built D-tube wing is going to be a lot easier...

Hi Tim,

I think that it is a matter of personal preference as to "easier". Other than cutting a bazillion ribs, I truly feel an I-Beam model is much easier, and quicker, to build. Especially quicker, since you are only limited in how fast you can trim the ribs at the rear once everything is set up.. and CA glue really speeds up the whole process. Having built many wings of all types, the next best to an I-Beam model is Bob Hunt's "Lost Foam" system. (and that counts regular foam wings..... I have completely lost interest in making skins and gluing them on) Plus, I have had three different people come to my house on a Friday evening and by Sunday afternoon they had USA-1s all framed up to include the wing and fuselage. We didn't "build straight through", either.

The added benefit of an I-Beam model is that it self aligns.

Big Bear

Steve Helmick · « **Reply #16 on:** September 03, 2011, 10:08:51 PM »

Oddly enuf, most of the 2 to 4 engined stunters I've seen, heard, or read about, had the need for more nose weight than had been expected. Because of that, I'd say the Messerschmitt 110 would be a much more suitable design than the Grumman Skyrocket, Mosquito, or Gloster twins. Both the Skyrocket and Mosquito have been published, both by Jack Sheeks, so I would suggest starting with the Mossie plans and hammering it into the Bf 110 of your dreams. Both used a pair of Fox .35 stunts (talk about vibration problems!)...but a pair of .25LA's would be a much better choice. I would still suggest making the nose weight box good for at least 4 oz., just because...

Steve

PS: Besides, the Gloster's gun arrangement was just dopey...

Dennis Holler · « **Reply #17 on:** September 06, 2011, 08:20:13 PM »

I'm still sketching... was playing with the nose profile and the engine placement tonight. Also made some changes to the canopy and raised the top profile of the fuse up about 1/4" at the rear canopy, it looks much better now, the old line was the Stuka base line. I think its getting somewhere. I think it can be made to look pretty scale like with some effort. Ha, sorry about the double images

Steve Helmick · « **Reply #18 on:** September 10, 2011, 03:45:56 PM »

I know you're hot for the Bf 110, but I like the Bristol Beaufighter real well. The config. would work nicely for a stunter, with good vertical CG likely. Looks like some versions had a flat horiz. tail, and some had dihederal in the stabalizer. Nice option. Nose is a bit short, but if you extended the nacells, you could make the nose a little long and it would look balanced and proper. The link should take you to some pics, data and 3-views.

Steve http://en.wikipedia.org/wiki/Bristol_Beaufighter

Dennis Holler · « **Reply #19 on:** June 14, 2012, 10:50:52 AM »

Finally talked to Jack Sheeks about the 110 at the last Sportliners meeting. He liked it so far

so ah I think I'm gonna start cutting stuff

It's just another tree and they grow fast

I'll post some pics as i go just for laughs

Bill Little · « **Reply #20 on:** June 30, 2012, 12:28:47 PM »

Quote from: Dennis Holler on June 14, 2012, 10:50:52 AM

Finally talked to Jack Sheeks about the 110 at the last Sportliners meeting. He liked it so far so ah I think I'm gonna start cutting stuff It's just another tree and they grow fast

I'll post some pics as i go just for laughs

HI Dennis,

It's been a couple weeks now......... any progress??

BIG Bear
RNMM/AMM