HSD 105mm F-16 EDF Jet

[Aros]

Okay some interesting things here. First off Lcacing for the first time ever with this new model I looked straight down "Bird's Eye View" at the top of my Vstab/Rudder and wouldn't you know it? It indeed had a curve to the left! Not massive but certainly noticeable when looking for it. So I straightened it out using my hands (the foam is pretty malleable) and now it looks much straighter. That alone makes me wonder how that was contributing to the flight characteristics I have noticed thus far?

Secondly, I measured the throws as accurate as I could with my digital caliper...Here's the numbers. I measured from the trailing edge outboard side closest to the wing tip. Note: The trim setting is to the right to compensate for the left roll. Not a lot but just as an aside...

Not sure what to make of them:

AILERONS

LOW RATES:

LEFT UP THROW MEASUREMENT: 4.3mm
LEFT DOWN THROW MEASUREMENT: 3.7mm

RIGHT UP THROW MEASUREMENT: 7.2mm
RIGHT DOWN THROW MEASUREMENT: 7.1mm

HIGH RATES:

LEFT UP THROW MEASUREMENT: 8.5mm
LEFT DOWN THROW MEASUREMENT: 8.2mm

RIGHT UP THROW MEASUREMENT: 9.9mm
RIGHT DOWN THROW MEASUREMENT: 8.2mm

So looking at these numbers what immediately stands out to me is the limited throw especially on low rates coming from the left aileron. 4.3/3.7mm versus 7.2/7.1mm right aileron. High rates also shows a discrepancy in throw between the left up aileron (8.5mm) and right up aileron (9.9mm). Now bless it all I am just a pixel pusher and not an aeronautical engineer, lol. If anyone can look at these numbers and help me translate based on what I have described with the flight dynamics so far I promise you 10,000 Good Karma Points. Also, I am highly interested to hear what your throws are in mm's compared to mine. I need to crack this nut once and for all.

[Aros]

Hugh Wiedman I should have offered up a version of the video sans music so you could hear when the power cut out. It went from sounding like a typical WOOSH jet to silence! Like a glider! Only the sound of airflow. Spooky! And don't you worry my friend, next time I am killing that bogie!! LOL!!

PaulZ I will definitely be hyper-examining the aileron settings for sure. Throw may be part of the issue but I suspect there's more going on. I have always had a cam on the port wing tip and had many flights without a roll tendency to the left like that.

Lcacing I will most definitely recheck the elevators for symmetry...They "look" even to me but granted that's at a few feet away glance. Rudder will also be double-checked. Yes, Throttle/Elev mixing was turned off from the start. This bird is going to get a thorough re-examination of ALL control surfaces. I see enough videos and hear enough from others with this model where it flies super stable. I have to think there's something missing...I may not be the best pilot but I am better than this jet makes me look sometimes I swear it! LOL!

Also, if you guys don't mind can you give me a quick callout of your aileron settings? Low/Hi/Expo? I apologize if you mentioned them somewhere earlier in the thread. I want to do a quick sample size of where others are at compared to me. MUCH appreciated!

I am at 15% expo and I will measure the throws and post them here to compare to your guys' settings...

[Lcacing]

Aros sounds like the CG is almost there. I would check the elevators to make sure they are even, that would induce the un commanded roll. Also mine came with a slight twist on Vertical stab so had to add couple of clicks on rudder, double check that. You did end up turning the throttle/elevator mix correct?

[PaulZ]

Aros sounds like a great RC day! Congrats! She will reward you. Not sure why you have an induced roll to one side? Double check the aileron trims. It's weird that plane does not roll. The A-10 however rolls to the right and I had to trim that out.

[Hugh Wiedman]

Aros Still in one piece with no repairs needed is a win in my book! Really noticed when you kicked in the gyro! Hardly noticed when you cut the throttle, but it did look like you were heading in for a kill shot on a bogie hiding in the trees!

[Aros]

Holy Hell it's always something.

After driving an hour to a place we were scouting to fly this bird (and found it wasn't viable) we eventually made our way to White River Amphitheater which is the usual spot. It was a great day for a Sunday Drive so all good. We also stopped off at a local club's new field (actual full scale grass 2500ft runway) and chatted with some members. Looks like it will be a viable place to fly! They plan on mowing the grass even shorter than it already is and right now as is I could probably take off on it. The winds were whippin' pretty good but I decided to fly anyways. Rotated a good 50-100 feet earlier than the maiden so I could immediately tell the CG was better. However, it still was really wonky on the roll...She seems to want to really roll to the left. At times nearly 90 degrees and I have to fight to get her level! Upon thinking about it, I think my aileron throws are simply too low. I think I lowered them so much because I recall the recommended were WAY too sensitive, but I must have over-compensated and now I don't have enough.

So I had to switch to high rates. Still bouncing around pretty good (you can see it in the video) so I couldn't fine tune the trim like I was hoping due to the winds. But once I switched on the Cortex gyro WOW what a difference! Immediately smoothed her out. Unfortunately as I went to change the rate switch I inadvertently hit the throttle kill switch! At first I didn't realize it and I just said "Holy $$$$ I have no power!" Right as I am heading for the tree line. I was about to cut over for an emergency landing when I realized what I had done...Hit the switch, gained power back and barely missed the trees by the skin of my teeth!! That was a disaster I don't want to think about how close it was to happening.

So I came in for an emergency landing aka "I May Have Just Soiled My Shorts So I Need To Check" and managed to get her down without too much fan fare thanks to a strong head wind.

Takeaways:

1) CG felt much better.
2) Still wonky on the roll. Need to increase my throws for more authority when it's needed. Lateral Stability check only showed a minor lean to the left from the RunCam2 placement.
3) Power was much improved over the old system. Will really be able to tell in calmer conditions.
4) The Cortex gyro ROCKS! I have my gain set to 40 and it felt about perfect. Might even increase it to 45. What a difference.
5) Thank God for this robust gear. While these first two landings haven't been my best or worst, they still show how durable they really are.
6) I need to fly this jet away from buildings, light poles, tall trees, highways, neighborhoods PERIOD.
7) My BP meds have been put to the test lately, lol!

[Lcacing]

Aros Good luck on the re-maiden flight!!!

[Lcacing]

Good luck! Once you get the CG right you will love this F-16! I am maidening my A-10 tomorrow morning.

I also have the A10 (90 mm upgraded), Start with CG 10mm further back from book CG.

[Aros]

Thanks PaulZ I am looking forward to it! Good luck with your A-10, you are going to LOVE her!

[PaulZ]

Alright PaulZ Hugh Wiedman and other thread members, I am prepared to offer up the second sortie for better or for worse. Video to follow.

Good luck! Once you get the CG right you will love this F-16! I am maidening my A-10 tomorrow morning.

[Aros]

Alright PaulZ Hugh Wiedman and other thread members, I am prepared to offer up the second sortie for better or for worse. I think the former, hopefully. Someone I know through selling him a plane and is relatively local to me has found a decent spot to fly this big girl. A church parking lot/roadway that is 45 minutes from my house. More than worth the drive as it looks to be the place I have always coveted to fly my bigger models which is free of light poles, buildings, trees, curbs, houses, etc... He sent me a photo and it looks like a long paved road with flat surroundings. (Happy Dance).

I have NEVER flown this jet (I've owned all three...V1/V2 and now V3) without major obstructions and high approaches so I am ECSTATIC. I installed my Demon Cortex gyro so that's ready to go. I moved my batteries back appropriately to get within what I believe is a more "pilot-friendly" CG within the 175-ish range. So other than Dumb Thumbs or some Series of Unfortunate Events, I am ready for a nice flight. Video to follow.

[Aros]

Nice. When I get some extra funds I plan on grabbing some more RT 5500 70Cs which I have had great success with in this jet.

[PaulZ]

Yeah I had to carve out some of that side foam where the port-side 2S battery resides in order to get both to fit that far back. Feeling much better about this second flight.

I only fly 5000s in this bird since they fit better, still all the way back. 3:30min flight times are fine for me.

[Aros]

That looks right. I have my batteries as far back as they will go.

Yeah I had to carve out some of that side foam where the port-side 2S battery resides in order to get both to fit that far back. Feeling much better about this second flight.

[PaulZ]

Okay I was able to get a more accurate CG measurement. Here is the location of my Admiral 6000s (photo below) for a 175mm CG which a lot of flyers have found success with. It's quite a bit aft of where I had them for the maiden so no wonder I was having takeoff roll issues and maxing out my up trim. I was probably flying around 160mm if that! Yikes. I am feeling a lot more confident with this placement for the second flight. I also found out about a church in Graham, WA (about an hour drive from me) that welcomes RC flyers and it is a nice relatively long runway with no immediate obstructions. So I may go check that out this weekend.

That looks right. I have my batteries as far back as they will go.

[Aros]

Exactly! I always call on my "Flight Angels" for all my flights and being on Church grounds can only help!

[Hugh Wiedman]

Okay I was able to get a more accurate CG measurement. Here is the location of my Admiral 6000s (photo below) for a 175mm CG which a lot of flyers have found success with. It's quite a bit aft of where I had them for the maiden so no wonder I was having takeoff roll issues and maxing out my up trim. I was probably flying around 160mm if that! Yikes. I am feeling a lot more confident with this placement for the second flight. I also found out about a church in Graham, WA (about an hour drive from me) that welcomes RC flyers and it is a nice relatively long runway with no immediate obstructions. So I may go check that out this weekend.

Can't do better than to fly on the church property, doesn't hurt to have the big guy on your side and an angel on your shoulder!

[Aros]

Okay I was able to get a more accurate CG measurement. Here is the location of my Admiral 6000s (photo below) for a 175mm CG which a lot of flyers have found success with. It's quite a bit aft of where I had them for the maiden so no wonder I was having takeoff roll issues and maxing out my up trim. I was probably flying around 160mm if that! Yikes. I am feeling a lot more confident with this placement for the second flight. I also found out about a church in Graham, WA (about an hour drive from me) that welcomes RC flyers and it is a nice relatively long runway with no immediate obstructions. So I may go check that out this weekend.

[Lcacing]

Hugh Wiedman I was referring to the original post of 634 grams for the Admirals. For sure the RT have the edge over HRB and Admiral. I found that the 5500 RT45c is a good compromise in power/cost, specially when they go on sale for around $86. I’ve also used the RT 6250 35c on 90mm EDF’s.

[Hugh Wiedman]

Here are the weights off the batteries, I don’t use the HRB 5000’ in the F16 simply because I prefer longer flights, I can essentially use the other 3 in the same position and the plane still feels locked in. I haven’t felt the need to go further back than 175mm (gear down) because as PaulZ mentioned, you end up having to add elevator mix to compensate for a tail heavy plane during landing.
From what you described it sounds like you have some gremlins running around. Lol. You mention your batteries are at the leading edge of the black foam, check out where mine are.

Lcacing Looks like I have almost identical weight measurements given there is about a 3-7 g difference in each brand of battery from one to the next, virtually negligible. I've added photos of the weight of a couple more batteries for those interested, the Admiral 6000 50C, the RT 6250 35C and the Hobbystar 8000 100C. The weight of the Admiral is not a typo, it's the heaviest of the ones listed below (except the HS 8000), but it also tests out to have the lowest actual C from tests using the Progressive RC internal resistance meter (lower even than the RT 6250 35C). A quick table of the 5 with weight and actual C measured follows:

Battery Weight Actual C Cost

RT 5500 70 C: 801 g 35C $120
RT 6250 35 C: 793 g 28C $ 93
HRB 6000 50C: 823 g 33C $ 78
Admiral 6000 50C: 838 g 26C $124
Hobbystar 8000 100C: 899 g 28C $180

And there is a big difference in the power draw on an inrunner when using the RT 5500 vs the Ad 6000 (even though the actual C difference is 35C vs 26C). In my tests, initial full throttle on a RT 5500 70C was 118 Ah & 2810 Watts on the 12 blade 4068-1835Kv inrunner, and on the Admiral 6000 it was only 110.2 Ah and 2478 Watts, definitely noticeable on take-off. So Admiral needs to catch up. I'm not bashing Admiral, I have over 70 of their batteries and never had a problem, they just need to address the higher mAh 6 cell, with lower cost and higher actual C to compete with RT and HRB.

You can see that the Admirals are the heaviest of the 5500 to 6250 mah batteries but also have an lower actual C and unfortunately the highest price. I no longer use the 12 Admirals in anything, just the RT 6250 in all the outrunners (they don't need as high a C as the inrunners from my testing) and the HRB 6000 in all the inrunners. I also quit using the 8 RT 5500 I have, although it has the highest actual C tested, I wanted longer flight times where I was using them in my F-16 and SU-30. Now I only use the HRB's in those (and at $78 per battery, best value) and the Hobbystar 8000 in the F-16. It was too heavy for the SU-30. I know the actual C of that is low compared to the listed 100C, but I was actually surprised it was as high as it was, with 8000 mah and only an additional 75 g of weight, I knew it wouldn't test out anywhere near advertised. But my upgraded inrunner in the F-16 likes it, flies virtually the same as with the HRB, just an extra minute or more of flight time.