Yak 130 90mm

[xviper]

I can't be sure what year this was but here is the link of the PNP 8s that you could buy (before it went out of stock and has yet to come back):

https://www.rc-castle.com/index.php?route=product/product&path=470_471_514&product_id=6673

I had the 6s before the 8s system came out and this is what I put in it:

https://www.rc-castle.com/index.php?route=product/product&path=256_630_633&product_id=10200

[pmdevlin]

I managed a flight today! Took a while to figure out everything with the rats nest of wiring, but got there. After much bench testing, 1 of my 2 6s 5000mah 70 chl packs had dipped to 3.9v / cell so I dropped in the other fully charged one. I'm on a grass strip, it barely took off, almost stalled, once in the air very stable, I like it. With the batt all the way forward it climbed like crazy, took a lot of trim on elev. But, sadly it was very slow
the unmarked motor and esc are def not stock, so I'm going to risk 8s, see what happens. My thinking is someone swopped out the stock esc and edf for a reason maybe ill get lucky!

[xviper]

I would be cautious. The stock 6s Yak acted just like yours did - barely got off the grass and when it did, it stalled into a tree. If the tree wasn't there, it would have stayed airborne. An 8s Yak running on 6s would likely never leave the ground at all. Have a fire extinguisher on the ready.
A true 8s running on 8s should get off short grass in about 150', even though once in the air, it's not all that fast, just more competent and quick to accelerate.

[RRHandy]

I managed a flight today! Took a while to figure out everything with the rats nest of wiring, but got there. After much bench testing, 1 of my 2 6s 5000mah 70 chl packs had dipped to 3.9v / cell so I dropped in the other fully charged one. I'm on a grass strip, it barely took off, almost stalled, once in the air very stable, I like it. With the batt all the way forward it climbed like crazy, took a lot of trim on elev. But, sadly it was very slow
the unmarked motor and esc are def not stock, so I'm going to risk 8s, see what happens. My thinking is someone swopped out the stock esc and edf for a reason maybe ill get lucky!

I have the 8s version and thou has power to take off, it by no means is fast, it's heavy without the battery's. It flew fine but not much faster than the 6s, One of the guys at another club has one and we flew together and at full I just pulled ahead.

R.

[pmdevlin]

Well I went brave! Made up a series connector for 2 x 4cell packs, and plugged it in, esc would not arm, so my esc is 6 cell.
I'm really growing to like this plane just spent 2 hrs doing a manual set up on elevator to neutral out yesterday's flight trim, but the lack of power is an issue. I hardly fly anything past 2/3 ,throttle, this was flat out from take off, which it barely did, to landing, 3 mins 3.7 v per cell. It's too marginal to enjoy, I need to rethink this

[xviper]

Did you throw a 6s battery back in to see if it arms and runs? If it works, you're lucky and didn't burn something up. The 6s version of this plane was meant for a long, smooth, flat runway so it can get up to speed to fly. Flying won't be comfortable or carefree as you'll need to keep the throttle near max. As it slows down in banked turns, the sphincter will get a work out.
If you really like this plane and want to keep it, you should consider putting the 8s system I linked earlier.

[pmdevlin]

yes I then used a 6s, all was good, I did notice, I didn't check first, the ubec is rated as 6s, so I agree I was lucky. I'm struggling to come to terms with the cost now. Plane cost £200, I thought that was a good price as it all works, just the nose gear doors missing,. and I feel the nose retract is a bit weak. I wanted an 8s, It was sold as a 6s as the owner just didn't know,. he had it years in a shed,. never flew it. The expense there would be some batts. Now, as I pretty much know its 6s, to upgrade will be over £200, plus bats, making total cost way more than its worth. I would have been content with 6s as I don't fly fast, but it was so marginal on take off without ordnance, which I really want to use, Its now a big decision, I hate decisions!

[Evan D]

I think you are finding why it was discontinued. At first it sold well but many found it very heavy flying. It didn't take long for sales to drop off. We now have more powerful fans but we didn't then. This plane still has a core group of people that like it but add that spares are sparse and I think people are selling the ones they have. The FW 90mm F-15 and T-45 are similar.

[pmdevlin]

Yes agreed. If I had a proven 6s set up, I can keep the esc, because and batts I already have, its just a new motor and fan, just need reliable take off, and a reasonable cruising speed that can manage loops etc

[pmdevlin]

Ubec

[xviper]

Yes agreed. If I had a proven 6s set up, I can keep the esc, because and batts I already have, its just a new motor and fan, just need reliable take off, and a reasonable cruising speed that can manage loops etc

The older 6s would have a really hard time to do a loop from a level pass. You'd have to dive the thing first to get it moving before entering the loop. Even then, it could fall out of the loop before getting to the top, so you must have some altitude or it'll take a dirt nap on the way down.
If you go 8s, you can use the 6s batteries you have. Just buy a couple of 2s ones that match the brand and "C" rating. The 8s fan and HV ESC, however, will likely double the cost of your plane but in my opinion, if you really like it, it'll be worth it to be able to take off from grass in a fairly short distance and be able to do a loop from a level pass. If you are going that route, get the reversing ESC for those times you have a smooth runway. It's a heavy plane and will roll forever.