The XPB Stage 1 underway.

You're quite welcome to mention what you might like to see in a High Wing, cheap and cup holders are already in place ...

Wing tanks. Fuel tanks sitting over my lap or behind/under seat make me nervous....

Probably not, but anything happens to the tank, whether its something like a fence post or branch puncturing the tank or whatever I' rather it was as far away from me as possible. It's probably more of a psychological/personal preference thing, being trapped covered in fuel - worst nightmare stuff for me. Wing tanks are no guarantee it won't happen but makes me warm and fuzzy(er) than tank over my lap. My 2 cents

You may not walk away from an impact that ruptures a fuel tank - but if you have wing tanks, it reduces the chances of being covered in petrol, and it definitely reduces the possibility of immediate fire upon impact.

If you've ever had any modest volume of petrol spilt on you, you know how much it burns and stings, just by itself - and then you're just a firelighter waiting to be ignited.

A crash results in disorientation and major disruption, and the body and mind takes a minute to try to make sense of what has happened, to orient itself (often ending up being suspended upside down - disconcerting in itself), and to determine what bodily injury has been incurred, and how it affects movement. Being covered in petrol only adds to disorientation, adds to distress, and increases the time taken to re-orient oneself.

Anything that can delay the onset of any post-crash fire is important, as a fire commencing only leads to further distress and urgency to move, possibly leading to mistakes being made in post-crash decision making.

I've had an open container of petrol blow up in my face, and I can tell you, it's not something I want to relive.

I can assure you, your decision-making process when you're on fire, is definitely flawed.

So you think you're going to walk away from an impact severe enough to rupture a fuel tank?

How about bladder tanks in the wing roots, So how much fuel are we going to carry?, My bladder ( human one) can go 3 hours easy. But I find concentration diminishing in rough weather at about that time. 3 hours at 20 ltrs per hour (500kms?) + reserve, so 75 ltrs should be a good place to start? 3 x Bladder tanks, wings and underseat. Although I do like the header tank and gravity feed as I now have. Much less reliant on fuel pump/s. So 2 x 25 ltr. flexitanks and a 30 ltr. rigid header. one pump on the cockpit floor and a left / right/off tap . After some research "Fleximake" look nicest. but 40ltr is the smallest, oh well! you dont have to fill it right up? Glad that's sorted.

I think basing fuel tank size on bladder capacity is rediculous. I certainly don't want to be seeking fuel at every place I stop at, it might be ok on the coast but sourcing fuel at out of the way places is a nuisance. I say make the fuel tanks as big as practical I think 100-140 litres is the range to look at. That is enough to fly till the bladder is full and then fly home again without worrying about refilling.

Maybe two tanks of 25-35 litres in each wing would be ideal so it is easier to manage accurate part fills.

Not Ridiculous. I said it was a good place to start.............. I'm not sure what wing chord or profile thickness you're going to use, but 2 x 35 ltrs is quite a bag (wing) full ............Don't forget it's an alloy wing, not a glass wet one. AND you're going to go overweight, of that I'm certain.

ie: 140 kilos of fuel, tanks, pumps and taps.

200 kgs of people

100 kgs of engine and ancillaries.

25 kgs of baggage.

That's 465.

so, 135kgs for airframe, u/c, wheels and instruments?

Good luck.

( This is, of course an exageration, but you can see what I mean. What you want is not the same as what you need)

Fuel bladders sound like a good, safe idea. I was initially put off by the price and weight, but after all the things I did to my tanks, they are probably as heavy.

Not Ridiculous. I said it was a good place to start.............. I'm not sure what wing chord or profile thickness you're going to use, but 2 x 35 ltrs is quite a bag (wing) full ............Don't forget it's an alloy wing, not a glass wet one. AND you're going to go overweight, of that I'm certain.ie: 140 kilos of fuel, tanks, pumps and taps.

 

200 kgs of people

 

100 kgs of engine and ancillaries.

 

25 kgs of baggage.

 

That's 465.

 

so, 135kgs for airframe, u/c, wheels and instruments?

 

Good luck.

 

( This is, of course an exageration, but you can see what I mean. What you want is not the same as what you need)

Remember fuel is .72kg/litre so it'd be more like 101kg than 140. Nevertheless, I reckon you're right that you couldn't fit 2 people with full tanks - it'd be more for one person doing long trips. For two up you'd have to leave the outer ones dry.

But Mark Kyle would know more about this than me, I believe he's got long range tanks in his girlfriend. (That sounds a bit wrong.)

What you want is not the same as what you need

I could post hundreds of race car crashes demonstrating the validity of them.

ie: 140 kilos of fuel, tanks, pumps and taps.

200 kgs of people

 

100 kgs of engine and ancillaries.

 

25 kgs of baggage.

 

That's 465.

 

so, 135kgs for airframe, u/c, wheels and instruments?

Not Ridiculous. I said it was a good place to start.............. I'm not sure what wing chord or profile thickness you're going to use, but 2 x 35 ltrs is quite a bag (wing) full ............Don't forget it's an alloy wing, not a glass wet one. AND you're going to go overweight, of that I'm certain.ie: 140 kilos of fuel, tanks, pumps and taps.

 

200 kgs of people

 

100 kgs of engine and ancillaries.

 

25 kgs of baggage.

 

That's 465.

 

so, 135kgs for airframe, u/c, wheels and instruments?

 

Good luck.

 

( This is, of course an exageration, but you can see what I mean. What you want is not the same as what you need)

It costs hardly any weight to have the capacity sitting there empty until you need it. A much better alternative to carting around jerrycans

If you have the fuel capacity you can bet RAA will want to have full tanks included in your AUW.

Saying "I don't fill them up, so I'm not overweight" may not work....My tank capacity is 140 ltrs. I NEVER fly with full tanks, what's the point in carrying fuel you are not going to use ( outside mandatory reserve , of course). But Hey it's all about Bex's aeroplane, maybe there will be a choice of tank capacity?. Us city/coastal folks can fit alternative systems? Cheers, G

If you have the fuel capacity you can bet RAA will want to have full tanks included in your AUW.Saying "I don't fill them up, so I'm not overweight" may not work....My tank capacity is 140 ltrs. I NEVER fly with full tanks, what's the point in carrying fuel you are not going to use ( outside mandatory reserve , of course). But Hey it's all about Bex's aeroplane, maybe there will be a choice of tank capacity?. Us city/coastal folks can fit alternative systems? Cheers, G

Because that seems kind of strange... people could be 150kg each, so your seating capacity is 300kg.

What do you mean saying that I don't fill them up all the time 'may not work'. Each flight you (me) are either under MTOW or you are over, it is as simple as that there is no maybe about it. On flights 2 up with large people I can't legally fly with full tanks so I don't, quite simple really. When flying by myself on a longer trip I use full fuel well within the MTOW and reap the benifits thereof.

Is that the way it works though? They judge AUW on the capacity rather than the reality on the day?Because that seems kind of strange... people could be 150kg each, so your seating capacity is 300kg.

It is a legitimate statement to say " I never fill the tanks to full". Many aircraft in commercial ops operate on that same principle.

That's why if you are ramp checked you can be asked for your weight and balance check done on the day with the load you have on board then.

Ok, I see............. I thought that RAA being RAA would check the aircraft's Maximum Carrying Capacity and make sure that it's not able to go overweight. But of course that wont work because people's weight varies.

I stand corrected.

No RAAus work on empty plus and if your empty plus people plus full fuel exceeds legal limits for that category then you have to have a trade fuel for people/luggage.

Eh if you have a 95.10 with fuel capacity greater than that which would allow empty + pilot + luggage + fuel fuel you must in adddition to knowing the trade off permanently mark the tank with max legal see tech manual 4.1.4. And just to be pissy that's a requirement imposed by tech manual not the CAO and it is based on a 90kg pilot mass. If you are less than 90kg you can legally fill above that permanent mark ... it's just one of those weird motherhood parts of the tech manual that are only helpful for a single set of circumstances that 95% of the time never exist ... just weird.

they do have some guidelines for minimum possible loads, like 80kg pilot and fuel for xx minutes flight time

This came to light when people were trying to bring aircraft into RAA with questionable AUEW vs MTOW - ie they couldnt reasonably take off without breaking 600kg

Ok Bex..... you've had a long enough break, what's been happening in your neck of the woods old son?

Pete, you probably know Bex has recently been deeply involved in an intensive search for a cheap and reliable power plant for the XPB, that must contain, cutting edge technology.

He's still waiting to hear back from the most interesting and promising, power-source developer - the industrial-strength, rubber-band manufacturer.

Ok Bex..... you've had a long enough break, what's been happening in your neck of the woods old son?

Glad to get a laugh from you blokes occasionally.

Sorry to hear you've been going thru a rough patch, Bex.

Let's hope we can serve up some comic relief.

Sorry Guys, my Father in Law died 2 weeks ago, hasn't been a lot of fun of course, funeral etc, and now even more bad news down the track. You can't stop the life cycle but it certainly bites hard sometimes. China's on another holiday all next week, I'm in between factories, and the interim factory hasn't worked out well, was hoping to get into the new one this week before this holiday break, alas ... It's just one of those periods in life when nothing's working, we all go through them and it will be the past soon enough.Glad to get a laugh from you blokes occasionally.

Hope all goes well with the factory after the break, I don't think I'm the only one who enjoys seeing your progress.

Yes, there are some things that definitely slow us down or stop us altogether, but as we've seen by your posts you and your wife definitely have the ability to come through on top of things. My condolences to your family, especially your wife. Tell her that all of us here wish her well .