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I’m currently building an Avanti XS, I got the tank and thrust tube with the kit but am a bit unsure if I’m missing something with the tube mounting, the supplied former to hold the tube is too small, am I missing something??

I had to shave out some of the inner ID ‘bumps’ on mine too. I deepened the notches too as that allows more airflow for cooling. Not every pipe is made as exact as each other one by all manufacturers. Measure the OD of the pipe to get an idea of how much you need to remove, and relieve SLOWLY the tops of the bumps until it just barely fits tightly. Then relieve some in the notches to gain back the airflow, and finally round off the tops of the bumps to get a good fit. The pipe does not expand much at the rear end on that plane I found, but it does depend on whose pipe and how it was made etc. Start tight, as you can always relieve more. If you end up making the former too loose, you can paint the bumps and indeed the whole former with BVM Heat Shield. It adds a bit of thickness to the bumps...
Hope this helps,
Len

Yes JR Americas has had their challenges for a couple of years now. I got both of my XS’s from them. One in Canada and the one I built in Hawaii is now in Cali soon to be in AZ. When I needed a second Mini Avanti, the first one I had obtained from the fellow in Las Vegas, JR Americas was still waiting on the container. Likely, at least in my opinion, a tall tale. I emailed Seba in Italy and I was surprised at how little extra it was to ship just one plane from Italy to Canada, and how fast it came too! To be fair I think it was about $100US more to do it that way than to have JR Americas sell and ship it to me, but they have none and given the closure of JR Corp in Japan, I have no confidence that they ever will have any SebArt product again. I have ordered twice from Seba personally and both times it went well, other than a FedEx issue. The two Avanti XS’s I got from JR Americas, never came with pipes or tanks, as they are in a separate add on kit, which was never ever ordered by them, also the stands (I recommend the SebArt one highly) were never ordered either as far as I could tell. Seba had everything in stock, and shipped in a couple of days, taking a week to get to Canada. I suppose the drawback ordering directly from SebArt is the bank wire transfer. That is the only way he will ship anything, money first, then he ships. However; at least Seba has had what he says he will have, unlike another Italian firm’s very many missed dates. I guess this all depends upon how much you want the plane...hassle-wise that is. I can heartily recommend the XS, but to be fair I have only about a dozen flights on the two planes. In the first one here in Canada I had some gear controller issues so I got only 4 flights and then I was away for the winter where I built the other and got 8 or so on it. In HI we only get the runway on Sundays and maybe not even then. I did get very comfortable with the plane and it flies better than the Mini Avanti on which I had well over a hundred flights before donating it to the AZ Desert floor! My fault, zigged instead of zagged.

Hope this helps...
Len

Thanks for the detailed reply Len, will just open up the former to fit the pipe 👍

what servos are most commonly used? I have some Savox 1250 HV which are 8kg torque at 7.4v however the JP retract controller says to only use 6v? My last jet had the same controller but didn’t state a voltage so I used 7.4 with no problems, is this fairly common?

I tried using Savox servos on my first XS here in Canada, but the Futaba S-Bus system (with the proper decoders) seemed to have difficulty with them as they either oscillated about neutral (like an old Galloping Ghost system) or did not function at all. I removed the decoders and used Futaba S-Bus servos. I was trying to do the 7.4V thing too, but ended up using a Fromeco Sahara regulator at 6.2V. Now that plane had Electron gear so its not a good fit to your JP issue.

The second XS in the USA used the JP gear from SebArt, but I used the same S-Bus and regulator at 6.2V since the S-Bus doesn’t seem to like the Savox system. The XS doesn’t need super strong servos though. I think when I was using Savox in #1 I used 1256’s mostly except on the flaps. Again my issues were with the S-Bus system and I do like the Savox servos. I tried the S-bus with the Savox servos on the 6.2V regulator thinking it may have been the higher voltage, but they still went goofy, so I bit the bullet and ordered two new sets of S-Bus servos from Futaba.

Onto your specific issue with the JP gear: I would test the gear on 6.4 then 7, and finally 7.4V, if you are set on using 7.4V. I would simply add a regulator down to about 6.2V or so and run the whole system there. The only concern is the elevator servos as the 1250MG is only 63.9 oz-in at 6V. Obviously you won’t use 1250MG’s on the flaps. The elevator servos I used were 93 oz-in at that 6V. My sense of the thing is that 64 oz in is likely lots with one on each elevator, but I’m not sure about that, so don’t go by my numbers for this one.

You could always drop (resistor or zener diode) the voltage just to the gear controller, but that is a waste and it makes heat for certain. The other idea is to use a separate 6V battery to power the gear controller, and simply use a ground and signal wire set (no +ve wire) from the receiver to the gear signal input, where you use the +ve and -ve from the 6V battery for the gear controller. The -ve wires both go to the -ve input on the gear controller. This could set up a common ground but with gear there is no feedback loop so common ground is fine there since there is no chance the +ve feed from the rest of the radio system can get to the gear controller.

Sorry this got so involved...
Len

I am using a Powerbox Mercury SRS, Savox 1250 on all surfaces except flaps all on 7.4V, I’ve used this identical setup on a previous jet and not had any issues with the srs, I use a JR 28X and the dmss seems to work well like this,
the only reason I questioned it is the new JP retract controller says 6V input on the box but my previous one says nothing so I used it on 7.4, never had any issues though!! I might consider using a powerbox inline regulator just for piece of mind as there seems no benefit of running higher voltage on the retracts but as you say the Savox 1250 are only good if run on HV (63oz vs 111oz I think)

thanks for your help Len

You’re most welcome sir! It is a large difference from the 63 to 111 oz-in...
Enjoy,
Len

Hi,

can anyone comment on the recommended centre of gravity for the XS?
the manual says 230mm back from the leading edge, just wanted to double check this as it seems way further back than i would have imagined, way past the wing tube, just need reassurance it isn’t a misprint!!

thanks
joe

The recommended CG worked perfectly. Works out somewhere near the main gear.

Thanks Neil

My Cdn unit runs a Merlin 100XBL on the stock pipe from SebArt, and the USA unit runs on a JetCat P-100RX again on the stock SebArt pipe. Shouldn’t be problem for any 100 engine...
Len

The yellow scheme looks good. It looks as though the canopy is a grey tint unlike the blue on my blue version (which I removed).