finally a calm morning to conduct a proper first flight test. highlights below in sequence:

flown with 1300mah lipo

after power up gps module (HGLRC M100) oddly took some time to lock my 10sats minimum. i suspect the lengthy wire run and close proximity to the caddx vista are the obvious suspects. i can live with this for the time being. during flight it eventually locks 25sats anyway. 

this thing is uber quiet! you can barely hear it just a few meters away.

the caddx polar camera has decent image quality. i see some very nitpick issues but will need to point the accusing finger more precisely after further testing.

after a few short laps around the neighborhood i immediately performed GPS rescue (BF4.4.0) and it flew back as intended. oddly enough this thing was MUCH better behaved minus the nauseating rocking behavior of my AOS5 having the exact failsafe setup.

i did a distance run soon after and 1.5kms out my HD signal suddenly turned RED! hmm, i recall someone here mentioned stock antennas that came with the caddx polar pkg suck! well i think they really did suck! 

meanwhile RC link was excellent with very high RSSI dBm (-65) at 1km, LQ 100%, 25mw. since i turned back at 1.5kms the output went 100mw momentarily then settled to 25mw again.

i limited the remainder of the flight flying laps around the neighborhood at a constant 50-60kph. this is at 35-40% throttle input. i finally landed after 11min at 3.7V only. i think i can stretch this thing even further down to 3.6V coz it barely sips juice. ease off the throttle and the pack instantly recovers. unlike my AOS5 guzzler.

not bad for a first flight! it handles excellent for the intended use case. next will see how it rears the ugly head in windy conditions! i KNOW for sure it will have awful propwash handling. it will also have somewhat wobbly low throttle behavior BUT still flyable coz i have seen worse.

i believe this thing can be tuned to behave much better. after this then i shall further nitpick and diagnose the fpv image quality which for now i may slightly attribute to (very slight) jello caused by the tpu canopy. 

i learned a ton after this morning’s experience with a lightweight quad. 11min consuming 900mah with some endurance left on a 1300mah lipo is good. now i shall see where i reach the point of diminishing returns after trying out the various pack sizes on hand. otherwise krohsis is spot on you can get decent endurance with lipo after all.

all for now.

Hi mstc,

Now, I am confused. From the physics that I understand, the quad as illustrated
would be flying backwards since the nose is up. Consequently, the illustration 
doesn't make sense to me. Confusing. 

When the quad is in forward motion, regardless of the direction, the nose would
be down (required for forward flight) and the antenna would be pointing up towards
the sky. Is this not correct? 

Except for some LOS testing, the quad would normally be flown FPV with the goggles
and always be in forward motion in which case the antenna would be pointing up.
Is this not correct?

The point being that it would be extremely unlikely that the transmitter would actually
be in the Null zone cone.





Later, iFly  

Hi Hawk,

Quote:after power up gps module (HGLRC M100) oddly took some time to lock my 10sats minimum. i suspect the lengthy wire run and close proximity to the caddx vista are the obvious suspects. i can live with this for the time being. during flight it eventually locks 25sats anyway. 

The beige block on top of the GPS is an RF receiver. Yep, it has to be able to receive 
signals with minimal blocking. What is blocking it? Anything between the GPS receiver 
and the sky. Well, there could be some RF interference from the other antennas which 
just happen to be higher than the GPS module. 

Given what I have learned and experienced with GPS units, the location at the lower rear 
of the quad is less than optimal. Ideally, GPS units perform better when mounted a bit higher 
than the top deck frame plate. The rear/high location that I use has always performed very
well. Now, the GEPRC Tern LR40 has the GPS mounted high, but at the front of the quad.
The reviews that I have seen indicate that this is a much better location than the rear/low
position. 

The wires are likely not the problem especially not the length. The wires on my GPS are 
long and unshielded. At one point, I tried various wire and module shielding, however,
none of it helped and some made it worse. That said, you have a digital VTX, so you 
might try shielding the GPS wires with a  wire mesh sheathing material. Might help, 
might not, but might be worth a try.

Moving to the ELRS antennas, it might help to adjust them a bit as Mstc suggests. You
might keep the rearward angle, but angle each one outward a bit so that they form 
more of a "V". That would at least point them in different directions. 


Later, iFly  

(11-Mar-2024, 02:36 AM)iFly4rotors Wrote: Hi Hawk,


The beige block on top of the GPS is an RF receiver. Yep, it has to be able to receive 
signals with minimal blocking. What is blocking it? Anything between the GPS receiver 
and the sky. Well, there could be some RF interference from the other antennas which 
just happen to be higher than the GPS module. 

Given what I have learned and experienced with GPS units, the location at the lower rear 
of the quad is less than optimal. Ideally, GPS units perform better when mounted a bit higher 
than the top deck frame plate. The rear/high location that I use has always performed very
well. Now, the GEPRC Tern LR40 has the GPS mounted high, but at the front of the quad.
The reviews that I have seen indicate that this is a much better location than the rear/low
position. 

The wires are likely not the problem especially not the length. The wires on my GPS are 
long and unshielded. At one point, I tried various wire and module shielding, however,
none of it helped and some made it worse. That said, you have a digital VTX, so you 
might try shielding the GPS wires with a  wire mesh sheathing material. Might help, 
might not, but might be worth a try.

Moving to the ELRS antennas, it might help to adjust them a bit as Mstc suggests. You
might keep the rearward angle, but angle each one outward a bit so that they form 
more of a "V". That would at least point them in different directions. 


Later, iFly  

well taken on the gps module location. fortunately for my setup i still have the option for top deck location which is the most unobstructed. for now the vtx and dual dipoles which hover directly above the gps antenna may have impeded its ability to lock sats faster. i shall also splay the dual dipoles further after the glue stick hack.

(11-Mar-2024, 12:26 AM)hawk01 Wrote: i finally landed after 11min at 3.7V only. i think i can stretch this thing even further down to 3.6V coz it barely sips juice.

Did you need to manually take the battery down to storage charge level afterwards?  What was resting voltage?

I tend to land mine at around 3.55V because that would give me a resting voltage, after recovery, of around 3.8V.  I'm guessing landing at 3.7V would give a voltage of around 3.9-4.0V, which IMO is too high and would require manual adjustment down to 3.8V.  

Just wondered whether you adjusted yours down and if not whether you are seeing any damage/issues with capacity?

i fly down to 3.7V loaded and i think it recovers to about 3.8V+ only. admittedly i am not too meticulous with consciously having my packs ran close to proper storage voltage. in practice when i frequently fly the packs in consecutive days like now when i am testing the new build, the packs are just lined up on my desk for use with the intent of landing in the ballpark of half the capacity. i only charge to storage knowing it will not be used frequently in the coming days.

I run the batteries down as low as I can. 

Realistically, this ends up being about 3.0 to 3.3 volts on the OSD screen,
however, when checked with a meter the voltage is between 3.3 and 3.5 volts.
Plus, I don't manually return batteries to storage charge. I know, this might
not be the best for battery life. Yet, my batteries seem to last a very long time.
No, I don't track battery cycles nor how long any of them actually last. 

(02-Mar-2024, 04:34 AM)hawk01 Wrote: the build encountered a slight delay. i had to decide in favor of a suitable motor with M5 prop mounting in favor of Tmount. i got BH VY1507 1550kv replacements coming soon. these have a bigger motor volume compared to the Emax Eco2 2004 1600kv it replaces. although both weigh almost identical. would there be any benefit to the larger motor volume?

https://www.brotherhobbystore.com/products/vy-1507

Maybe you will get suitable motors at T-motor: www.tmotor.shop /shop.tmotor.com. :p