The XPB Stage 1 underway.

[Pilot Pete]

Getting very interesting and enjoying how this is all panning out. Can't quite picture the skin set up yet so will be great to see the end result to fully appreciate the how, what, where, when and why of it all. Cheers

 

 

[Jabiru Phil]

Could be that Bex is keeping us in the dark with his home built.

 

This is what he is REALLY working on.

 

The Incredible Flyboard Air

 

 

[bexrbetter]

Can't quite picture the skin set up yet

Well I might have to tone it back a bit yet, seems to be a little controversial and generally that's not good for business. May have to go for a similar, but not the same, more standardised foam sandwich setup, I'll think about it over the weekend.

 

As you can see a little from a few previous posts, and also elsewhere, traditions and creeds are quite well set in aviation and not easily disturbed.

 

This is what he is REALLY working on.

people probably think he's wearing a parachute on his back, bet ya it's a fuel tank.

 

 

[apm]

Bexrbetter, I think you should stick to your original design goals. Filter the comments for what they're worth, I dont think your market is with the typical forum member, maybe initially it is for a few kits, but most of us are flying and have strong opinions based on aircraft previously available. You have an oportunity to improve on past practices, so use materials where needed that are very efficient to manufacture, easy to build & safe to fly.

 

 

[Deskpilot]

Bex, follow your dream, do your own thing and forget the nay sayers. If Boeing can mix metal and composite materials, so can you.

 

 

[Pilot Pete]

Am I wrong in thinking that the frames are now molds for an inner and outer skin with the bracing molded into one of the skins ? I'm probably out of the ball park on this

 

 

[bexrbetter]

Bexrbetter, I think you should stick to your original design goals. ......You have an oportunity to improve on past practices, so use materials where needed that are very efficient to manufacture, easy to build & safe to fly.

They are my design goals and there are many methods available to achieve them that I'm working through.

 

As you know there are very strong traditions that have held the sport back and if you want to enter the marketplace then you can't just completely ignore those retarded backward ingrates or their sisters who they married.

 

Yep, you have to be very, very careful not to offend their values at all.

 

Am I wrong in thinking that the frames are now molds for an inner and outer skin with the bracing molded into one of the skins ? I'm probably out of the ball park on this

I only changed in an attempt to get rid of the multitude of bracing and have knock proof side skins.

 

It seems to be causing ruffles so I am re-considering my thoughts on it over the weekend - that started with mead (honey beer) and pizza last night ... another morning gone that I will never get back ...

 

 

[microman]

I think composite skins is a great idea - firstly it would be a bit lighter and secondly it gets rid of the horrible drumming that metal-skinned aircraft are susceptible to - I am guessing that once the various glass panels are all on you would simply join them together by using micro filler in the joins - sand it back and hey presto!

 

 

[Pilot Pete]

Please don't reconsider. I know were not the ones putting in the time and money, but I think it would be disappointing not to see how it all works out. I think if you don't look at this build method as a serious way to go, you'll end up regretting it. Who's to say what is the correct way to go with this aircraft. It's you're design after all. You certainly have my blessing to continue ruffling feathers

 

 

[bexrbetter]

Who's to say what is the correct way to go with this aircraft.

You've obviously never posted at HBA forums

 

You certainly have my blessing to continue ruffling feathers

Tackling human nature does dictate a lot of marketing decisions, you may have the greatest mouse trap in the world but it only takes a little poo-pooing of your product to cast doubt and that ignorance travels through modern social media rather rapidly. This happens more easily the more different from 'norm' your product is, so need to travel with some care.

 

 

[Pilot Pete]

I take it they tend to dictate what is and isn't acceptable at HBA. Do you have a thread running on that forum as well ?

 

 

[Pilot Pete]

Just checked and you do

 

 

[bexrbetter]

Just checked and you do

A build thread, and very fortunately build threads can not be responded to by anyone other than the OP, unlike here. There's some great regulars over there, but then there's a few others as well.

 

 

[bexrbetter]

A build thread, and very fortunately build threads can not be responded to by anyone other than the OP, unlike here. There's some great regulars over there, but then there's a few others as well.

Sorry, re-reading that just now may have come across as me like not liking responses to my build threads period, please understand that was specific to that forum, while in difference, I enjoy the comments, feedback and banter at Rec Flying.

 

 

[Pilot Pete]

Yep. I knew where you were coming from as I had seen that mentioned on the forum

 

 

[bexrbetter]

So need to get serious about the rudder and dorsal fin now.

 

I have looked at various methods but most of the methods used to take a vertical surface from a horizontal surface don't really grab me, so I have made a vertical surface to begin with simplify and put fastener loads in shear rather than pull.

 

I have simply split the rear section of the turtle deck, added a spine, which adds a lot of strength anyway, and will take my fin/ruder vertically from the sides of the spine, built a basic mockup of it today and works well, looks something like this

 

 

 

[kasper]

Simple design but consider the fact that without a fin root fillet and/or a lot of fill you are creating a water gathering channel along both sides of the fin base - corrosion control in this area might be an issue

 

 

[Marty_d]

Neat solution.

 

Simple design but consider the fact that without a fin root fillet and/or a lot of fill you are creating a water gathering channel along both sides of the fin base - corrosion control in this area might be an issue

It should be fairly tight - wouldn't a narrow fillet of silicone solve that?

 

 

[kasper]

Neat solution.

 

It should be fairly tight - wouldn't a narrow fillet of silicone solve that?

Yep it would ... but without it its a seam with a fold line that will allow water to sit in the seam ... airframes sitting outside for long periods tend to have issues with corrosion on these type of seam.

 

 

[bexrbetter]

Correct.

 

Simple 3D's don't show all detail. There are weatherstrips of various profiles that will do the job, or sealants as mentioned.

 

So starting mapping it all out today, testing rudder shape with an old bit of blue fiberglass, should get a result in a few days time. You can quite clearly see the spline here and the gaps are because it's only got a couple of rivets holding it all together, as is the entire turtledeck also only held on by a few rivets ....

 

 

 

 

 

[kasper]

Correct.Simple 3D's don't show all detail. There are weatherstrips of various profiles that will do the job, or sealants as mentioned.

 

So starting mapping it all out today, testing rudder shape with an old bit of blue fiberglass, should get a result in a few days time. You can quite clearly see the spline here and the gaps are because it's only got a couple of rivets holding it all together, as is the entire turtledeck also only held on by a few rivets ....

 

[ATTACH=full]46766[/ATTACH]

 

[ATTACH=full]46767[/ATTACH]

 

[ATTACH=full]46768[/ATTACH]

Wow!! you really like directional stability don't you?

That's a HEAP of side area behind the CofG to keep it dart like ... but consider that the IMO huge fin will need a really strong spar to take side loads you might consider reducing the fin area a bit to allow lighter spar/fin primary structure ... weight that far back is really hard to deal with and on a first build you NEVER get the damn CofG where you want/expect it ... and long battery cables to deal with a CofG unexpected outcome are both unattractive and add quite a lot of weight if current drop is not to be an issue.

 

 

[bexrbetter]

Wow!! you really like directional stability don't you?

More to do with the angle of the pictures, the stab area is safely large'ish, but not huge.

 

Looking for a nice, soft to fly cruiser, not a Lancair.

 

 

[Marty_d]

What sort of hinge system will you use for the rudder?

 

 

[bexrbetter]

What sort of hinge system will you use for the rudder?

2 heim joints.

 

 

[bexrbetter]

So there's all these little things being done that will suddenly all come together over the next couple of weeks I hope, and that will go from looking like I'm doing sweet nothing at the moment, to suddenly advancing forward in great steps.

 

I did a dummy run with the tail design today after many, too many, iterations trying to find a simpler, cheaper way.

 

Came down to, for the moment at least, a pretty simple, almost 2 dimensional in feel, aluminium design that's stupidly easy to make, and due to some importance in alignment, even has "matched assembly holes". First run ever had it assembled in less than an hour with mistakes and adjustments (pre cut and bent parts).

 

The tail is sitting 50mm~2" too high as it needs to be slipped in down through the rear/rear tutledeck yet (see post #541 and #545 above).