|
|
Message from Steve Robinson in Australia re: IV-PT cabin ferry tank
---------- Forwarded message ----------
From: Stephen Robinson <steve@wabillboards.com.au>
Date: Wed, Jul 13, 2011 at 4:36 PM
Subject: RE: TURTLE Packs
To: Dave Saylor <dave.saylor.aircrafters@gmail.com>
Hi Dave
Your welcome
We too were concerned about the overfilling wings and potential damaging them.
As an operating procedure I used to start on the LH tank to check that
it worked.
After start up I would swap to the RH tank.
Taxi and takeoff on the RH tank and once established in the climb turn
on the bladder and pump.
That way I knew I had pulled at least 20 or so litres out of the LH
wing and couldn't possibly over fill it.
The other concern was overfilling and venting fuel which would then
reduce range, which this practice also prevented.
In flight the transfer pump kept up with the engine flow and about
2.30 hours later I'd hear the facet pump tapping away indicating it
was empty and Id turn off the pump.
There was usually a bit left in the bag but Id leave the valve open an
over the next hours or so the cabin pressure would squeeze out pretty
much everything.
I found I needed to move the bag about occasionally especially when
nearly empty to make sure the outlet was at the lowest point.
Also I forgot to mention I sat the bag on a couple of thin polystyrene
sheets, one on either side of the outflow valve. This kept the bag
sitting on a smooth level base and stopped fuel running into the outer
sides of the bag.
Id toyed with the idea of a frame with a canvas sling like a wing
support frame but it was a lot of work and weight for no real gain.
I found it easiest to secure the frame to the plane and just one strap
over the top of the frame to hold the bag.Wasn't needed, the bag never
moved and I never felt any movement of the fuel either.
It felt the same has having 2 pax on the back seat, only they didn't
talk or fidget to upset the autopilot
I used to disconnect the auto pilot every hour or so and re trim the
plane as the fuel burnt off. I don't have auto trim on my STEC 55
I used the main wing spar bolts for the front anchors, just a simple
plate with nylock nut just tight enough so the bracket could rotate
slight.
The rear shelf, drilled thru and made up anchor points about 3 inches
in from each side.
With a piston engine you might want to figure out a fuel management
plan for him to ensure no over filling goes on.
The other simplest way will be turn on the pump and watch the fuel gauge.
Happy for the info to go onto the LML.
If your guy gets to Perth look me up
Ill probably have some room in hangar for short stay as well
Regards
Steve
-----Original Message-----
From: Dave Saylor [mailto:dave.saylor.aircrafters@gmail.com]
Sent: Thursday, 14 July 2011 6:05 AM
To: Stephen Robinson
Subject: Re: TURTLE Packs
Wow! I couldn't ask for a better answer. Thanks, Steve, that's just
what I needed.
I was concerned that the flow wouldn't be enough but we're using the
same pump as you, and we're burning less than 20 gallons/hour. Sounds
like the few sections of 1/4" line won't be a problem.
I was also a bit worried about pressurizing the wings, but that
doesn't seem to be a problem either.
If you don't mind, I'd like to post your email to the Lancair Mail
List so it's in the archive for others. You have some very useful
information there and it might help someone some day.
Thanks again, look for N196TX coming through your area next summer some time.
Best Regards,
Dave Saylor
AirCrafters
140 Aviation Way
Watsonville, CA 95076
831-722-9141 Shop
831-750-0284 Cell
On Tue, Jul 12, 2011 at 5:46 PM, Stephen Robinson
<steve@wabillboards.com.au> wrote:
> Hi John
>
> Ill start the start at the start and go thru the lot.
>
> I didn't build the plane so my apologises for a few gaps
>
> My 4PT is 999 kg empty weight.
>
> I have the earlier kit with the slight larger wing ( not the quick build option) and the under floor belly tank.
> Wings are placard as holding 245 litres per side and 66 litres in the belly.
> In practice I've never been able to get more than 235 in each wing and 60 in the belly.
> Even if I pump out all the fuel with the pumps.
>
> The builder ( Frank Fry) designed the fuel system so the belly was pumped up and over to the RH wing via a little facet pump which moves about 100L per hour.
>
> He also installed a cross feed pump from the LH wing to the Rh wing, uses another faccet pump at about 100L an hour.
>
> This meets the turbine certification requirement that all fuel can be taken from a tank ( RH) without changing tanks.
> That's is the belly and the LH wing can all be pumped into the Rh wing and all fuel used.
>
> Not sure if its an Australian reg but anyway that how it works.
>
> Laurie has the same set up.
>
> My fuel lines are -8s from the tanks to the selector to the engine. Fuel is sent via a 250 L/Hr electric pump, originally a Dukes fuel pump ( think it was the original fuel boost pump for the Conti engine) but they no longer rate for continuous use so I bought the larger pump from Diemech in Florida which is the ???
>
>
> The belly transfer and cross feed lines are all -4 lines.
>
> The LH wing to RH wing cross feed tee's off the -8 line with a -4 reducer to the faccet pump then across to the fuel return inlet of the RH tank, this was the fuel return line for the continental engine installation.
> There is another -4 fuel return line in the LH wing which is blanked off.
>
> The belly tank/ pump tees into this -4 line and the facet pumps have internal check valves to stop them back feeding.
>
> Ill do a diagram and attach as it will make it easier to understand.
>
> See pic of the Turtle Pac in the plane.
>
> I order the heavy weight rubber, it stank like heel for quite some time, my best advice is on receipt, inflate with air and stick it in a well ventilated area for a couple of weeks before using.
>
> I found on using straight away the rubber smell was bad enough to male my son feel sick and my eyes would water from the fumes. Also with Jet A1 if froth is trapped inside during fuelling it will smell ( BADLY) of Jet fumes, maybe not a dram with the Avgas version. The rubber is soft and pliable, even the heavier jet option, In fact Id suggest the heavy option even if using with avgas.
> At time of ordering they fitted the -8 fitting for me and a longer filler neck, make sure it long enough to get well clear of the cabin , if air trapped while fuelling it will blow back and spray everywhere. Mines 4 ft long and Ill change to a 6 foot for the next trip.
>
> The tank sits on the back floor area.
> My rear seat drop in and held with Velcro as is the seat back. I remove the centre belts for the install.
> When filled the bag wedges in nicely and is very secure, I still use a few tie down just in case. You don't feel the fuel sloshing about and it has no effect on the plane at all.
>
> However when full the lower half presses quite firmly against the side panels and I was concern the panels would rub on the control rods and cause binding.
> I then built a simple frame from aluminium angle and that sits like a little cradle and support the bag and stops the pressure on the side panels.
> The pack will hold 265 litres but in practice as its compressed into the back seat area it will only take about 240 litres.
> Its also not round when filled more a squashed oval shape.
>
> I ordered the bladder with the -8 fitting with the intention to tee into the main fuel lines and gravity feed into the main supply lines, Hmm no way my mtc guy would allow that!
>
> With the turbine he was worried that if a slug of air got into the system then the engine could surge/ flame out, unlikely but possible and not desirable on a 900 nm ocean crossing to New Zealand.
>
> We engaged an aeronautical engineer to design the system.
>
> His design was so simple and effective
>
> We disconnected the LH tank cross feed ( capped off) to the pump and feed the bag into that pump. A -8 to -6 reducer at the bag outlet, a simple on /off ball valve fitted and then a length of -6 hose down to a -6 to -4 reducer and into the pump.
>
>
>
> The bag is now pumped via the existing cross feed pump over to the RH wing.
>
> The engineers paper calcs showed the transfer pump at 100L/hr would struggle to keep up with the fuel flow of 120 L/hr needed by the engine.
>
> Flight tests showed that the faccet pump was able to move appox 120 litres an hour and kept pace with the engine burn rate. Even thru the -4 lines.
> Interestingly enough with the pump turned off the bag still flows about 80 or so litres an hour.
>
> The cabin pressurisation will squeeze the fuel out, in fact it so empty that its like its been vacuumed out. It may have a litre left if that in at the end.
> I suspect the better flow was a combination of the pressurising force feeding the pump.
>
> Before installing I weighed removed components such as carpets seating seatbelts etc, and re did the calcs for the CG.
> See attached Excel. Its pretty tight on but all just in.
> My plane will porpoise with a rear Cg and be a pain to fly, however never experienced a problem with it.
>
> For my trip I also had a 15 Kg raft siting on top of the bag and sat phone case and few odds and ends, this restricted baggage to about 10 kgs in the back.
> On one occasion I did fill right up and left the raft in the baggage which made it porpoise again but the tank quickly empties and the CG came back in after about 15 mins or so.
>
> My vent lines are the smaller ones ( 1/4) , sorry not sure on that. I assume you meant the wing vents?
> In short the system worked great.
> It now has a 1800nm range, still air no reserves and I've done a number of 1400 nm legs in her, bit sore on the bum though.
>
> Hope it all helps , welcome to call me if you need it.
>
> + 61 8 9349 5692, just check your times please.
>
> Ill be at Oshkosh too next week.
> I've got some more pics somewhere and Ill see what I can find
>
>
>
> Cheers
> Steve
>
>
>
>
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: Dave Saylor [mailto:dave.saylor.aircrafters@gmail.com]
> Sent: Wednesday, 13 July 2011 7:20 AM
> To: Stephen Robinson
> Subject: Re: TURTLE Packs
>
> Hi Steve,
>
> Thanks for helping out. Seems like a good place to get in trouble and talking to someone with experience is great.
>
> I understand your plane is a turbine. My customer's plane is piston.
> That said, there should be a lot of similarities.
>
> Do you know if your wing vents are the standard 1/4" outlet, or were they enlarged?
>
> What size is the plumbing from the tanks to the wings? Turtle uses 3/8" outlets--were you able to use the same size throughout the installation? For example, we had to neck down to -4 for the pump fittings, 3/8 everywhere else.
>
> Laurie said you transferred at about 30 gallons/hour. What kind of pump did you use?
>
> Sorry you asked yet? ;-)
>
> How did you arrange the valve or valves?
>
> Did you put the tank on the back seat? If so, how did it affect CG?
> Ours is right at the aft limit with the tank full.
>
> I'm sure I'll have lots more questions. Thanks again, I really appreciate your help.
>
> Best Regards,
>
> Dave Saylor
> AirCrafters
> 140 Aviation Way
> Watsonville, CA 95076
> 831-722-9141 Shop
> 831-750-0284 Cell
>
>
>
> On Tue, Jul 12, 2011 at 3:21 PM, Stephen Robinson <steve@wabillboards.com.au> wrote:
>>
>> Hi Dave
>>
>> Laurie sent me your email.
>>
>> What would you like to know
>>
>> Regards
>> Steve
>>
>>
>> Steve Robinson
>> WA Billboards
>> Ph 0411 518 049
>> Fx 08 9207 2708
>>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1390 / Virus Database: 1516/3760 - Release Date:
> 07/12/11
>
-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1390 / Virus Database: 1516/3762 - Release Date: 07/13/11
|
|