Pitbull 2

[oipigface]

Jason, I think the R7008SB uses FASSTest encoding rather than FASST, which means that it won't work with my 12FG. Thanks for the thought, though.

[oipigface]

I was asked on the slope this afternoon how much narrower the PB2 tailboom is than the PB. The answer is that measured immediately in front of the tailplane, the PB is 25.5mm deep and 21.5mm wide. The PB2 is 21.5mm deep and 17.5mm wide. These figures are all approximate. The girth has diminished by around 10mm.

Does this mean it is weaker? I'll not be able to say until I've had a go at breaking it.

[drewetm]

24 minutes ago, oipigface said:

I was asked on the slope this afternoon how much narrower the PB2 tailboom is than the PB. The answer is that measured immediately in front of the tailplane, the PB is 25.5mm deep and 21.5mm wide. The PB2 is 21.5mm deep and 17.5mm wide. These figures are all approximate. The girth has diminished by around 10mm.

Does this mean it is weaker? I'll not be able to say until I've had a go at breaking it.

John

There is theory that the smaller the girth, although it maybe structurally weaker the laws of probability  mean it is less likely to break. If you have an hour and plenty of refreshments for me ..............

Martin

 

[mikef]

 

18 minutes ago, drewetm said:

There is theory that the smaller the girth, although it maybe structurally weaker the laws of probability  mean it is less likely to break. If you have an hour and plenty of refreshments for me ..............

Martin

OK I'm interested .....  Tell us more....  

Starting with the assumptions.

[natxopedreira]

On 24/11/2017 at 10:58, oipigface said:

It's a Baudis built 2S Li-Ion pack, 105mm long:

No, Stu, despite the fact that the noseweight is almost as efficiently packed in the nose as possible, there is little room to waste. From the moulded edge of the equipment bay to the tip of the inner nose is 220mm, and as you can see below, the Rx, its wires the noseweight and the battery fit in quite comfortably. Note that unlike in a Pitbull, the servo locations are moulded and therefore absolutely fixed.

The noseweight is 43mm long at the moment, but it will probably need shortening to get the CG right. So that leaves >=72mm for the receiver, and the wiring. (The noseweight looks to be bigger than the inside of the nose in this picture, but it isn't. The camera is lying because the noseweight is closer to it than the nose.):

 

The receiver in the photo is a FrSky TFR6-A, which has end sockets, and is 45mm long. This leaves 27mm for wires, which is more than adequate. In fact, because the Pitbull 2 has no fuselage ballast tube, it is quite easy to get a hook around the wing servo wires and pull at them through the joiner aperture (gently!) to bring the plugs back a few mm. The shorter Futaba 617 (which is available only with sockets on the top) will not fit in to this fuselage in any orientation without modification, because the case is too wide to fit bottom down (with the plugs protruding upwards) and the plugs together with the depth of the case are too long to fit sideways on. 

I shall probably use one or other of these Rx's, but if I use the Futaba, I will have to fit extension sockets hardwired to the pins.

Any thoughts about these options? I don't know of any others. I am still using a Futaba 12FG which requires FASST-compatible receivers.

There aren't many options for aerial routing, either, Stuart. What I have done in other models is take one straight back along past the receiver and servos, and then fit a vertical tube somewhere in a moulded deck, so the aerial ends are are orthogonal, as the instructions always advise. There's not much in the way of moulded deck here to drill through, though, so I may fit a tube running across the fuselage glued to the little bit of deck just in front of the servos. Any other ideas? Incidentally, I've never bothered too much about the things you mention, and I've not had any obvious problems.

Can i ask you about that li-ion pack?? i understand that its recommended by baudis... its 1600mha

Did you have experience with those packs? How many flight time per pack?

Im asking because im looking for a rx pack for my fosa as the lipo i bought did not fit  so im looking again.

In that post i was asking and only one person found 18500 reliable for f3x use... and i was asking on a panasonic 2000mhs so im surprised that baudis use a even lees capacity one.

Also nice plane you bought !!! 

Thanks

 

 

[satinet]

Less capacity can be better as lower capacity generally has high current output.

In some situations you could actually get longer flights with a 'smaller' battery. I.e if the larger battery suffers voltage drops.

[oipigface]

2 hours ago, natxopedreira said:

Can i ask you about that li-ion pack?? 

 

 

Yes, you can ask, but I am the wrong person to ask about batteries. It is the one recommended by Baudis, and it is short enough to allow space for everything else. That's about all I know about it.

[oipigface]

3 hours ago, drewetm said:

John

There is theory that the smaller the girth, although it maybe structurally weaker the laws of probability  mean it is less likely to break. If you have an hour and plenty of refreshments for me ..............

Martin

 

i don't think that the laws of probability are much use in understanding physical phenomena other than at the subatomic level.

[oipigface]

I've finished the installation. I actually needed a few grams more than the 166 I mentioned the other day to get the CG to 104, (which is the centre of the wing ballast tube), and I've mounted a couple of 5g wheel weights on top of the battery. They will probably come out again after a couple of trimming flights. As it stands I can vary the CG between 104 and 112.  

I've also ordered ballast for the joiner. Assuming that the wing area given on the 3-view is the area including the tailplane and bits of the fuselage that are allowed by the rules, the max permitted weight is 3976g. The airframe with all the gear installed weighs 2485g, and the tungsten I have for the wings is 1345g, which leaves the total weight less than 200g under the max. So I have ordered a couple of brass pieces from a local precision milling firm to be made up according to the diagram in Graeme's post above, which will be plenty. (I managed not to forget to subtract 1/2mm from the dimensions to allow wiggle room!)

[Peter G]

From my CAD overlay of the 3 view, I think the 56.8dm2 is just the wing area. I reckon you have another 5.5dm2 approx if you include the tails, which would take max weight up to about 4670g.

You can often get the full details on f3x vault but the Pitbull 2 isn't listed as yet.

[oipigface]

1 hour ago, Peter G said:

max weight up to about 4670g.

Well, I wish I had read this half an hour ago! I spent the last half hour working it out. I make it 4682g max. It's always good to cross-check, though. Thanks Peter.

So the strong layup will take no more than 852g in the joiner. Three brass and one tungsten will be about 1kg, so the max weight configuration is probably 4 tungsten and 2 brass in the wing, plus a full joiner. 4 brass is only 50g short. Given the prices, I might just go for that. I haven't found out yet how much funny shaped tungsten will cost, or if it is possible from the usual source.

Steel joiner would probably do as well.

[oipigface]

Pitbull 2 is now ready for its maiden. I checked with Baudismodel about CG and wing area. Here are the replies: "The ballast tube in the wing for Pitbull 2 is located approx. at 105mm from the LE. Pitbull 2 can be flown from 96 to 110mm CG, so the ballast box is in between of that range."  "Wing Area: 56.8dm2 / Elev. Projected Area: 5.79dm2" The areas are a little different from the ones I calculated, particularly the tail, but I may not have been using  the correct angle. Whatever, the 800g or so that 4 brass joiner inserts add will be on the conservative side.

I also bought some green tape and my camera still seems unable to get the colour right:

 

OK. What's the weather forecast?

 

[Martin Church]

Nice Model John look forward to seeing that fly at White Sheet soon

[oipigface]

Other prospective Pitbull 2 pilots may be interested in the fact that the hole in the wing saddle has been made larger than it was in the Pitbull, so that the annoying mechanical lock that could occur when demounting the wings of a Pitbull doesn't occur with the Pitbull 2.

Sunday at Whitesheet looks like a possibility, or Wednesday next week.

[krvedaa]

Received my Complete Pitbull 2, overall happy, concerned by tight fit. Was not happy that V-tails needs to be worked
to fit, that irritate me, because I paid to not have this hazzle. I am not able to Mount the V-tail as it is, Wonder if they ever
had it on when preparing the model? Anyways a couple of pics of my Orange / white Pitbull 2.

[Les]

39 minutes ago, krvedaa said:

Received my Complete Pitbull 2, overall happy, concerned by tight fit. Was not happy that V-tails needs to be worked
to fit, that irritate me, because I paid to not have this hazzle. I am not able to Mount the V-tail as it is, Wonder if they ever
had it on when preparing the model? Anyways a couple of pics of my Orange / white Pitbull 2.

Looks great mate.

I'm getting a bit fed up being told mine will be dispatched next week,this was five weeks ago now.

Three e-mails since and the same we are just finishing the installation of the fuzz and it will be dispatched early next week, RIGHT we'll see. 

Never had this problem with my first two Pitbulls.

Is it just that they are that busy?

Well I don't know but if they give you a dispatch date they should try and stick to it,NOT HAPPY AT ALL.

[isoaritfirst]

There’s your problem Les. 

Should have just had the wings fitted out. 

They haven’t yet found how to get all the bits in the fuz. 😲

[Martin Church]

Must be really busy with all the people paying the extra 450 euros for 3 weeks turn around

[Les]

10 minutes ago, Martin Church said:

Must be really busy with all the people paying the extra 450 euros for 3 weeks turn around

I wouldn't mind so much but I've sent three emails over the last five weeks and each time they tell me the wing installation has been done and they just need to do the fuzz.

It dosnt take five weeks to install two bloody servos.

I paid back in September. 

May be your right and they are wanting to sort out the three week turn around jobs first.

I'm going to send another email asking them to get it sorted or I want my money back. 

Not happy at all with the service from Baudis this time.

 

 

[Martin Church]

Does seem a rather strange offer Les that you can buy extra time in overtime & weekends to get a model in 3 weeks.

If everybody did that who’s getting there's first surely it’s first come first served first then a limited number of quick turn around for the wealthy.