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-   -   1:10 B-1 Lancer twin turbine (https://www.rcuniverse.com/forum/rc-jets-120/11701090-1-10-b-1-lancer-twin-turbine.html)

ltc 08-02-2022 09:54 AM

1:10 B-1 Lancer twin turbine
 
Has anyone ever seen one of these or have additional information?

https://www.fokkerc.com/product/rock...1-lancer-1-10/


tp777fo 08-02-2022 12:56 PM

That makes my Avonds Fouga look like a paper airplane.

Halcyon66 08-02-2022 01:30 PM

Interesting yet not sure about wood being used in the main spar box, maybe there is other reinforcement not shown.

No matter what may have gone into the design and calculations there is a line in the sand regarding building large scale wooden turbine models.

Regards,

invertmast 08-02-2022 06:17 PM

Im 99.99% it hasnt been built yet. From what i can see, i would expect a lot of changes to be needed for the sweep structure and pivot to be structurally sound.

David Gladwin 08-03-2022 01:16 AM


Originally Posted by Halcyon66 (Post 12738076)
Interesting yet not sure about wood being used in the main spar box, maybe there is other reinforcement not shown.

No matter what may have gone into the design and calculations there is a line in the sand regarding building large scale wooden turbine models.

Regards,

https://cimg7.ibsrv.net/gimg/www.rcu...816c8c042b.png

Halcyon66 08-03-2022 01:40 AM

What a truly pointless post, yes we can look at full scale airframe that were made in the 40's, that were a mix of wood and metal and had 100, 200, 300 aeronautical engineers designing the airframe.

Didn't you have the issue with the large scale airframe in another thread, whereas your senior moment of flying over the pits and missing the runway were highlighted? Yet not now.................

Yet why not post the 1/2 scale Gripen that exploded at Jet power or do you not know the difference/stress between turbines and prop airframes?

This is not the PowerBox forum so why are you posting?

Regards,

jofunk 08-03-2022 08:10 PM

I guess it depends on the definition of a "wooden" jet. Once you put a piece of plywood into the structure then you are building with a composite. If plywood is considered wood then there is no limit to the size wooden jet you could build. The dura mold process is plywood and Howard would of put jet engines on the goose if they were available. I built a !/4 scale F9F. The airframe is 95% wood It has been flying for 10 years. My only limitation was building something that was reasonable to move. When it comes to stress, just because its powered with a turbine dosen't mean it has more stress on it. Anything can be under built or overstressed, turbine or prop.

mongo 08-03-2022 08:37 PM

as long as it flown in a fashion that represents a scale supersonic capable bomber, and not like a sport jet/fighter, probably not going to amount to much chance of problems anyway.

Halcyon66 08-03-2022 10:21 PM

Turbines can stress a airframe much faster than a prop, props have a inverse relationship with airspeed where as a turbine benefits due to the increase in mass flow. It too has a speed limit yet it is higher than a prop. There is also a gyro effect of a turbine spinning at 100k, that few people factor in. As you know a turbine can increase speed very quickly and that catches a lot of pilots.

Your F9F which is think I saw a build thread on years ago is an impressive build, yet it does not have a swing wing mechanism. I would estimate this B-1 at coming out at 50~60kg at least if they are looking at dual 210s, the designer could come in with some FOS calcs and then everyone can take another look. The load on the main spar box and the wings would be considerable, lets not forget the tail inputs even just casually flying it around.

In regards to the Goose that used a process of high heat and pressure with all kinds of resins. All on a very serious industrial scale, not RC toyland. They also went that route as it was war time and were constrained by lack of materials. Pretty sure this B-1 is not going to use the same technique.

I already made the point of yes it can be done with wood and a pile of aerospace engineers. Not sure if this is the same thing.

So of course you can build a lot of things from wood. Not stopping you, or anyone going for it.

Regards,

Henke Torphammar 08-04-2022 02:01 AM

There are a lot of these fancy looking renderings along with CAD files for laser cutting popping up now. Talented artists for sure but I bet very few of them are actually built and tested. There are a guy on facebook making new CAD files every other day offering like 200 different plans. For smaller parkflyers I think that approach might work, but when we sort of wander over 3lb of take off weight it needs more engineering to be safe.

A kit like this are probably only useful for a static display model.

Halcyon66 08-04-2022 02:38 AM

Completely agree, one can make anything you think of yet the numbers don't lie. Just because it works does not mean it is safe.

RC does 6,8,+ g's easily and when you work the numbers on a 50+ kg frame it does not look good.

The Goose cost millions and flew once and got Hughes in a world of trouble, not the best measuring rod.

The method for structural analysis is lost on most, putting 100kg on a wing is not a winner there is a lot more to it.

Regards,



jofunk 08-04-2022 06:55 PM

There is no line in the sand regarding building large scale wooden turbine models. Poor engineering, inferior material, and flying an airframe beyond it limits is a different story. The same goes for composites.

Halcyon66 08-04-2022 09:03 PM

In the case of wood the law of diminishing returns plays a role as at a certain size no matter how much more material you add you will not gain any more structural integrity, it will actually start decreasing.

Would the Goose have flown if it was just plywood, no infused resins? Yet you imply that is still wood. If you want to talk wood, talk wood. No CF here and there, no glass on the wings and fuse just wood and Elmer’s. That is wood.

Does you F9F have any glass on the wings or fuse, carbon fiber or metal spars/joiners, composite tubes in its construction or is it all wood. You said 95% so am I to assume the 5% is lg and turbine?

Regards,

David Gladwin 08-04-2022 10:53 PM


Originally Posted by jofunk (Post 12738453)
There is no line in the sand regarding building large scale wooden turbine models. Poor engineering, inferior material, and flying an airframe beyond it limits is a different story. The same goes for composites.

Absolutely correct.
Birch ply, balsa and spruce. 400 mph, 2,500 hp and thousands built.
Another being built in UK, the Peoples Mosquito.
https://cimg5.ibsrv.net/gimg/www.rcu...a8cecfc0e.jpeg

Halcyon66 08-04-2022 11:09 PM

David, strange how those who believe they are experts think resin infused wood is wood,. Make it out of wood and lets see, cannot seem to get your head around that can you?

I just looked at the F9F thread from 2010, wood fuse covered in glass, foam cores covered in glass and metal main spars. Didn't bother to go any further.

Yet somehow that airframe according to the builder is 95% wood, are you kidding????

You got maybe 50% wood, 35% foam, 10% glass and 5% metal, excluding the LG and turbine.

How about you make it again 100% wood and see how it holds together, as you said any scale can be made with wood.

The pic is a 1/3 scale P-47 I was flying 22 yrs ago. The fuse was re-enforced fiberglass, wings/tail were foam core with obichi, carbon fibre and glassed, engine mount was carbon, main gear used golf buggy wheels and the motor was a monster 3W-240B4 quad and it came in at 65kg.

It was 95% wood as well.

Regards,
https://cimg4.ibsrv.net/gimg/www.rcu...8738bc24bb.jpg

David Gladwin 08-05-2022 12:45 AM

Dear Gods !!
The original Mosquito did NOT have resin applied. It was fabric and then doped.That worked very well as it did on the pressurised Vampire T11 fuselage, (similar to the Mosquito) on which I did my advanced training back in 64. No failures I can recall.

The Achilles heel of the wooden Mosquito was the glue, the “cement” resorcinol, ,
which eventually failed, and was later replaced by a more modern glue, urea based, more resistant to heat and humidity.

I guess the NZ built Mosquito, now in the US, was built with even modern adhesives as will be the forthcoming new UK build for which they have received thousands of drawings from B Ae so it will be authentic.

I am no expert on wooden structures but have spoken quite recently to people who are, at the de H museum at Salisbury Hall where you can see and examine various aspects of the Mosquito’s structure.

The Goose May have given Hughes a lot of trouble, the only trouble the Mosquto caused was to the enemy !

Now, you mention gyroscopic effects of turbines, please elaborate. Davies does not mention it in his book, Kermode says it is insignificant and RR does not even mention it. What can we, they, learn from you ?
Coffee finished !

Halcyon66 08-05-2022 12:52 AM

Imagine if you actually knew something...................guess another senior moment?

Why do you try so hard to stay relevant? PB forum, is dead now are you going to destroy all the other threads?

The Duramold and Haskelite process was first developed in 1937, followed by Gene Vidal's Weldwood and later the Aeromold process produced by the Timm Aircraft Company. In the United Kingdom, the De Havilland Aircraft Company (founded by Geoffrey de Havilland, a cousin of Olivia de Havilland, the actress who dated Howard Hughes in 1938) used similar composite construction for aircraft including the DH.88 Comet, DH.91 Albatross, the Mosquito, and Vampire. The aeromold process differs in that it is baked at a low 100 °F (38°C) at cutting and forming, and 180 °F (82°C) for fusing together sections after the resins are added.

Regards,

invertmast 08-05-2022 12:26 PM

As someone who is currently upgrading an RC model that is of similar size as this B1, i find it highly unlikely that a fully built up model would fall below the 100# LMA max for a turbine powered model and be structurally capable or withstanding 8+ g's. My 1/4 scale project has shown 8g's in a 60* banked turn at a moderate 120mph flight speed to keep it within the boundaries of your average size flying location. This is a model that is basically a round-e-round model that isn't exposed to aerobatics. On this project of mine, i have made significant use of molded fiberglass components where structural necessity is not required and fiberglass reinforced lite-ply structures with significant lightening and all i was able to shave off of one component is right at 15 pounds.

This B1 as drawn, IMO is significantly lacking in many structural area's (specifically the wing pivot, pivot box and H.Stab structures). Then we bring in the complexity of the swing wing and the H. stab pivot locations, both of which look to be improperly positioned, especially the H. Stab pivot. I am tempted to purchase a kit just to try one, but without an available source for landing gear, that will not happen.

jofunk 08-05-2022 02:11 PM

H66 it is unfortunate that you have it in for D.G. It looks like some hostilities developed on a different thread....... A healthy debate reveals a lot for people to consider and can be fun.................... Now let me defend my wood Panther..... The foam cores make up no where near 30% of the weight of the airframe. Regardless of the weight of the foam we would agree on the wings could have been built up out of wood and be just as strong... The aluminum plug in do not make up 5% of the weight of the plane. The aluninum plug ins were built in to make the wing removable to transport. They wouldn't be necessary for strength and wouldn't be there if I made a one piece wing. The spar would be all wood. There is no exotic building material in the plane, no carbon fiber , no carbon tubes or rods. Just glass cloth and West Systems if that is considered exotic. So foam, aluminum glass and resin 5%, the other 95% wood. Unless you do not consider plywood wood. When you fret about the line in the sand about building with wood and challenge me to rebuild my plane using just wood and Elmers glue (which I like) who is building big airframes like that? I would say practically no one. So big airframes being built out of wood should be low on the list of concerns we should have.





jofunk 08-05-2022 02:30 PM

When it comes to gyroscopic effects of turbines stressing airframes ,I have heard more stories about 3D airframes destroying turbines........ If you would like to verify, start your turbine on the stand, run it up, and start violently rotating it 90 degrees to the spinning axis. Parts will eventually start coming out of the back of it.

jofunk 08-05-2022 02:37 PM

And by the way there will be millions of airplane geeks disappointed when they find out the Spruce Goose is not made out of wood. Thats going to be a lot of explaining to do.

Halcyon66 08-05-2022 03:46 PM

I am lost, you indicated you can make any large scale RC model out of wood. Then you back that up by saying who would do that? My point exactly.

You never answered my question, would the Goose hold together if there was no pressure/heat infused resin? The process has a name for a reason, Duramold.

Most people know very little about the Goose other than bits here and there, implying it was made from off the shelf 2 x 4's is all part of the romantic glory days of that period. If they truly are airplane geeks they will know how the wood was treated to increase its strength, they would also know it was birch not spruce in the process.

The fact that it never flew out of ground effect, leaves a lot of ongoing questions to actual on going structural integrity.

So in summary the Spruce Goose was made from birth not spruce, that birch had been through an serious industrial process (probably highly toxic for the day) and it finally got airborne for the grand total of 26 seconds and never flew again. I don’t know what it cost yet in today’s dollars would probably be sh&loads.

Don't let the truth get in the way of a good story.

It is similar to saying something is made from steel, yet it has been specially treated with additives in the manufacturing process to make it stronger. So is that still steel or chrome moly for example?

We are going to have to beg to differ on the wood thing, wood is wood unless it has been treated. Them it could be classed as potentially anything.

Regards,

jofunk 08-05-2022 05:38 PM

No, Who would build it the way you described and apparently worry about. But then again when someone builds one with a tough as nails finish of paper and Elmers glue you will move the goal post and disqualify the technique because Elmer"s glue is resin.

Every wood and ply model jet is held together with some sort of resin.

As for the Goose, maybe not. but a 1/10 scale model of it with a 32' wing would hold together with wood and plywood........... and of course nails, I mean glue.

Now answer this about the goose, It weighed 300,000 pounds. subtract the weight of the resin and the metal and what ever else you can think of. How much birch is left to make up the difference?

After being in trouble for being over budget the Gov. demanded proof it would fly, even though the war was over. Howard didn't have to kiss their *****, just fly it for a few seconds and leave it in the rear view mirror. If the war would have gone on the goose would have transported troops over the ocean and would've eventually have jet engines on it.

jofunk 08-05-2022 05:55 PM

Its chrome molly steel alloy. It is all metal. It's not similar to Duramold.

Halcyon66 08-05-2022 05:59 PM

As said all the romance of the glory days.

26 seconds yet it was going to be flying all over the world.

Wright Brothers longest flight on that faithful day was 59 seconds.

Regards,


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