I have been putting several test flights on the Vector in recent days. Up until today I've been running two 3s2100 packs hooked up in parallel to provide the motivation, and using a 3020-12 (old style nomenclature--kV~1090 rpm/volt).

Results have been a little surprising. Yesterday I made my first full pattern flight--taking it easy on the lower pullouts. What is surprising to me is that the Vector seems to less draggy that the Nobler was. By this I mean that I am flying 4.8 and 4.9 laps and using about the same power as the Nobler. Now I am running a higher rpm---8200 rpm than the Nobler (~8000 rpm), but using the same 12-6 prop. I was assuming that the slightly heavier Vector (~48oz with the 2 packs on board vs 44 oz for the Nobler) would require more rpm just to keep up the level lap time (I am using exactly the same lines as I was using on the Vector). The Nobler was flying 5.0-5.1 laps.

Other observations--boy does the Vector corner and just stay there! That's good. However it does seem lighter on the overhead maneuvers than the Nobler did. However with the light winds of the last few days, even the light tension was fine for all needed maneuvering. I am guessing the lighter tension may be due to the slightly heavier airframe and the tighter maneuvers----I may be bleeding off airspeed in the much smaller maneuvers that I am doing with the Vector.

Today I simply setup the Vector with the Nobler "guts", a 3020-16 (kV=880rpm/volt) and my standard 4s2100 "Nobler Pack". This lightens the load ~4oz over the two 3s packs. I setup for a 5 minute flight with rpm=8200. I decided to skip some of the level laps after takeoff and the inverted flight --"just in case". Well I needn't have worried--as I pulled out of the bottom corner of the first loop of the square eight, the spinner-prop-collet came flying off the plane! As Fred points out, if it was going to come off, that was a good place for that to happen!

I just looked at the truncated data, and indeed it looks similar to the 3s pack flight data I already have. I am trying to get it setup for Sig, and it certainly will be a race to get there.

I have ordered some ThunderPower Prolite 4s2600mAh packs since I think eventually I will want to lengthen the lines, and maybe "splurge" a little (like Crist  ) on the power. Fortunately they seem to only be an oz heavier than my 4s2100 packs--a good tradeoff, even if they cost ~50% more ($99 vs $63). The question is whether they will be here for Sig or not.

What is interesting is that the prop/spinner/collet are all still tightly connected to each other. Also this was exactly the same combo that I have been flying on the Nobler (and the same motor too) so I am not sure what exactly is going on.

Anyway I have a few more collets/prop adapters so I should be ok. I do plan to wipe off the motor shaft with some acetone to make sure for the next flight.

Alan,
Sounds like the 2 planes are very similar enough to use the same "power".  Keep us posted on how it all shakes down.  See you in a week or so.  All the best in getting it worked out.

Alan,

Some thoughts on your first few flights.

Have someone outside the circle check very closely that your wing is dead level both ways.

Move your lines forward by about .25 inch (this will increase the tension upstairs)

If still light on the lines add about 3-4 grams more tip weight.

DO NOT REUSE A COLLETT THAT HAS COME OFF IN FLIGHT !!!!!!!!

Do not overtighten a collett as it will pull the taper too far into the bore and expand it....bad outcome!


Kim.

Made a full flight today at lunch on the e-Vector40. I include a plot from my data recorder. I wouldn't say this is a final configuration at all, but it isn't too bad. Since I pulled ~1800mAHr out of my poor 4s2100mAHr pack, I will need to cut some time off the flight for the next few days until my larger packs arrive.

Note added: the FMA charger claimed it put 1683mAHr back, so about 100mAHr more than what it claimed after a Nobler flight. Still a bit too much.

A couple of comments: From simply looking at the peaks of the laps from the end of the flight and measuring the time, I am still flying 4.9s laps on the plane. The recorder says I am turning the 12-6 prop at 8000 rpm (even though my Phoenix 45 ESC is set for 8100 rpm---I figure the error on absolute rpm numbers must be at the few % level (probably not crystal timed!). I probably will drop the rpm another 100 rpm or so to get the laps at 5.0. Even that said, I don't feel particularly hurried by the plane. I think the overhead tension is slightly improved, but I only had increased the position by ~1/8 inch. I now increased it ~1/2 inch and we will see on the next flight!

In case you are really anal and count the laps (like a stooge I know!), I did short the laps after takeoff and during the inverted flight, which then were left at the end (the flight still was my standard 5 minute flight). Like I mentioned before, I wasn't sure what to expect at the end of the flight and thought flying level at that time might be better than in the middle of the clover!

Anyway my ETA for my ThunderPower Light 4s2600mAHr packs is Monday. According to FedEX they are coming from Saskatoon. Oops, I see they just arrived in Winnipeg!

Alan,

Do you have any pictures? Sure would like to see them, nothing better that a new bird.

John

Actually I haven't quite finished with the covering trim and the cowl attachment. I was getting a bit frustrated, and decided I would first fly it and see if it was going to be worth the final details or not. I am glad I did that, because I learned a few things about how I was going to jam all the batteries and ESC inside the nose. It seemed a lot easier to work with the Nobler Fiberglass cowl setup.

I have this weekend to at least get it in "Way-standoff" appearance order. Also need to put on my AMA #'s. So I'll try and get a photo at that point. I have to say that it isn't going to be a Front-row plane!

All I managed to do this weekend was to figure out how to make the cowl attachment. I replaced the 3020-16 (kV=880) with a new 3020-780 motor. Also decided, (for the heck of it) to boost the PWM rate from the 12kHz stock value to 26kHz, and set the target rpm for 8000 rpm (expecting to get ~7900 rpm which I did get). Lap time was ~5.3 s which felt pretty good, and with the leadouts forward, the tension in the upper hemisphere felt pretty good. According to the recorder, I pulled 1542mAHr out of my standard 4s2100mAHr pack. My charger usually claims it puts less than the recorder claims I use, so I tend to side with the charger, but who knows. This "extra" frugality may come from the battery being "prewarmed" i n my car this morning. Outside temps are in the upper 80's, and I'm guessing the car was ~100F when I jumped in it at lunch today. So there is that, the allegedly more efficient motor (~5%) and perhaps another 5% form the higher pwm rate.

Here is the plot and also a photo--still without the final trimlines (and AMA #).

Slick looking bird, Alan. Love those tiny noses.

Tell me about your movement of leadouts. I had always thought that raking them aft would allow yaw more outward ( leading to the outside of the circle) and give greater line pull everywhere. The speed guys, so I was told, set their ships up to have the centerline tangent to the flying circle, so there was no outward yaw.  Sound like you moved them forward to get more pull at the top.

Everyone needs more pull at the top, especially me.

Thanks,

John

Getting closer Alan.  Though you still have 140mah to "waste"!

HI Alan,

Thanks so much for your regular informative posts. This kind of data really helps all of us e-people. Just a question on your Eagletree setup. Which sensor are you using for the rpm? Is it the wired-in brushless sensor, or the optical unit? If it is the wired version, then do you use both wires or just one? I find that the optical sensor is a little more stable, but then you need to mount it somewhere and also add something to the motor shaft with marks on it. Thanks.

Keith R

Keith,
I am using the brushless sensor, and only use a single wire of the two. Idiscovered last night that I think it is about 100 rpm off---I used my TNC tach, and it agreed with the CC Phoenix rpm setting.

I always wonder if the "hash" in the rpm plots are real or are noise in the sensor. I note that when I sometimes do motor tests and run the motor without a prop, the rpm trace is missing most of the hash--it looks less noisy. Not too sure what it all means exactly.

I also have the optical sensor--was planning to use it to see what the rpm of a glow engine was doing during a flight, but still haven't gotten around to doing it yet.

Keith,
I am using the brushless sensor, and only use a single wire of the two. Idiscovered last night that I think it is about 100 rpm off---I used my TNC tach, and it agreed with the CC Phoenix rpm setting.

I always wonder if the "hash" in the rpm plots are real or are noise in the sensor. I note that when I sometimes do motor tests and run the motor without a prop, the rpm trace is missing most of the hash--it looks less noisy. Not too sure what it all means exactly.

I also have the optical sensor--was planning to use it to see what the rpm of a glow engine was doing during a flight, but still haven't gotten around to doing it yet.

Thanks Alan, I was also wondering about the "hash", maybe Igor can tell us sometime. I think that the bottom line is that 100 rpm is close to a good resolution. If you think of tach's that have tried to add a lower digit for a 10 rpm resolution, then they jump all over the show. I've made a number of tach's through the years, and I always ended up with 100 rpm resolution. I've also tried to get down lower by using my R/C throttle control via a receiver. I watch the pulse width and rpm on my scope, and once again, 100 seems like a good number. I know that Kim says that the Schultze F2B esc has a governor that has a resolution of 20 rpm. If that's true then I would love to know how they get that right.

I found that the optical sensor works well, and you could maybe even add a couple of black stripes to the motor casing. The sensor has an infrared light (LED) in it, plus the pick-up sensor. They designed the sensor for heli's, and not for props out in the sunlight, like conventional optical tach's.

Keith,

For the optical sensor, I was thinking about using the spinner backplate as the surface, and use black ink to produce a number of light/dark segments. I figure the higher the number of segments, the higher the precision of the rpm measurement.

Obviously the sensor counts "ticks" for some short time segment, and then gets the rpm by dividing the count by that time. So if it looked every 0.1 second, at 8000 rpm, and a two blade equivalent prop, it would measure 26.666.. ticks. Now 8100 rpm would give 27 ticks on a 2 blade prop. I think that's why it is hard to measure rpm on a prop! With the electric motor, you can multiply the numbers by 7 (1/2 of 14 for the number of magnet pulses since I already doubled the original number for the 2 blades of a prop) to get 186.666 pulses in 0.1 s. for 8000 rpm  and 189 ticks for 8100 rpm.

If you integrated for more time (like 0.2 s, you would get a better precision). This is what I think happens for the tachs that give you an extra digit--or they are averaging a bit more (which is equivalent).

Sorry Alan, I must post this video!

Alan reprogrammed his controller with the following results:

<snip>..no reason to show it twice!

Your stooge,
Fred

Yes and this was going to be the killer flight.  I guess I was a little too frugal this time.
What comes to mind is that the best laid plans of mice and men often go astray!  

I got to put in three flights today with the ESC setup in fixed rpm mode--takeoff at 7600 rpm and flying at 8000 rpm. I left a data recorder plot in the "List your Setup" above.

When I charged the batteries back up, I am getting recharge values of 1283 mAHr and 1369 mAhr (3rd one in now charging). This really seems pretty low--even to me!

I am thinking this is at least partly due to how hot it has been in the last couple of days--it was mid 90's at lunch and after work. Also the batteries themselves were in the 85-90 degree range even before takeoff. It is known that the battery internal resistance drops with increasing temperatures, so you see more voltage at the battery terminal (so less amps are needed to make the same watts).

Also the thinner air puts less load on the prop. Lap times were still in the 4.9-5.0 s range on my 60 foot eye-to-eye lines.

I am guessing that cooler weather will load the batteries more. In any event, I'll probably put the new ThunderPower Pro Lites (4s2600mAHr) in the fridge until I need them. They arrived last evening. They weigh 8.4oz (without the Deans connectors), which is pretty light. However I reweighed my FMA 4s2100 mAHr packs and was a little surprised to see 6.9oz (I thought they were 7.4oz), so the TP ProLite would weigh 1.5oz more than what I have been using. Also have to do a little "dremeling" to get the new packs to fit in. Need to remove about 1mm on both hardwood mounts, and the new pack will slip right in.

Dennis,
No plans to try a pusher yet. Right now I am just trying to get ready so I don't make a complete fool of myself at SIG this weekend! At least I have the ESC setup right now!

I was thinking more about these current draws and now I am thinking a large part is just the less dense air. For straight and level flight it doesn't seem to be a big deal. However when you start maneuvering against gravity, that starts to me a problem. What I mean is that the prop is not getting its same amount of thrust due to the "high density altitude". Of course gravity doesn't care about temperature or humidity. I am wondering if my overhead tension is suffering a bit over what it was a week ago when the temperatures were in the upper 70's.

It is a bit hard to tell because I have been changing things so it is difficult to know what really is going on!

Hi Compadres,
This is why a 'needle valve" was deemed necessary by Hunt and myself. Just +/- 30 or 40 microseconds change in the running pulse-width from your timer is all that is needed, assuming the range is centered at the desired lap time on a moderate weather day.

Dean

Dean & Alan: I hear ya but still waiting to see.

I was getting my variation in power usage, but did not have any wasted flights.  My flight to flight variation was less than for a very good IC set-up.

* for a given day, I think it is easier for the pilot to make adjustments to flight to flight variations
* For vastly different sites, vastly different whter condidtions - it is possible that "needle" comes in handy, but again, I wonder how much different it should be to push for a change - and whether the cure is worse than the disease?

Having said that I am looking at adopting Alan's approach and pre-setting three close RPM's in ESC then using Will's throttle to sellect the one I want.

One more confusing factoid - I typically check the total mah restored to the battery INCLUDING the balancing stage.  I am slow-charging (1C rate) for something like 40-50 minutes to get back to 16.8V, but then the Equinox starts its cell balancing tap dance - and somewhere around 150-200 mah later the charge ENDS.  While balancing it is alternatively charging and discharging - so I am sure several of those mah are getting double counted.  I always recharge through the balancer, and I am not deep-drawing the cells, so I THINK I'm doing OK.


Alan: My pitmen and I are learning to launch a little early during the medium speed spool-up - mimicing the low power (and low battery stress) take-off you mentioned.  However, we have some data plots showing take-off as one of the high-peak manuvers!

Looking at my old aero book, I noted that the thrust from a propeller is, to first order, proportional to the product of the air density and the square of the propeller diameter. This suggests that, if a 12x6 prop is appropriate for standard SL conditions, a 11.2" diameter prop would be about right for a density altitude of -4000 ft and a 12.9" diameter prop about right for a density altitude of +4000 ft. It sounds like you should try that, Alan, so the rest of us can learn some more from you...

I think I acquitted myself ok on Sunday at Sig. Yes I sucked, but at least I flew! Came in 4th out of 12.  Strange I didn't get more points for making 5 landings on the second flight as I flew into a strengthening wind. However all in all I was pretty happy (also happy the plane survived!)

Lost a couple of maneuvers in the wind--primarily the vertical 8's and to some extent the hourglass. Overhead tension was pretty poor in the wind--much higher wind than I normally fly. I almost passed after flying a practice flight early in the morning--before the wind came up to at least be able to say I flew at Sig!  .

Jim Schuett--a pretty darn good flyer, gave me a couple of airplane trim suggestions. He said to add wing tip weight until I see it start to hinge and then back off. At the same time he mentioned that I may need to move the leadouts a bit more forward. This is just the same recommendation that Paul Walker's trimming chart recommends except in reverse order (move leadouts, then add tip weight). It is also consistent with Kim's advice.  These guys must know something! So that's the plan.

With all the wind, but cooler weather, the 4s2100 batteries still performed well My charger claimed I had 25% capacity left in all 3 packs. I love those cells! Right now I charged 2 up to 50% and put them in the fridge. I'm taking off for three weeks to Geneva Switzerland (work  ) after July 4th, so decided to store them until I get back.

I hope to get a few flights this week to get the plane better trimmed.

I did "tart up" the plane a bit before the contest--black 1/8" trim tape. It does look better--the trim tape breaks up the solid colors and helps hide some of the major covering flaws--at least for stand-off judging!

So overall I am pretty happy so far.

Nice job, Alan. 4th is not shabby, and with a new plane to boot!!

Another of my unending questions, how long are you flying on your 2100 mAh pack? I am just working up to enough time to possibly fly all the maneuvers and it looks as though that will require a little more than 80%C from my 2250 mAh packs (see latest report in "Trimming my Stunter). That's assuming the whole sequence can be done in 5.5 minutes. The secret seems to be slowing the plane down (using less energy --that 'ole v^2 function) and still keeping good line tension in the overhead stuff.

Also, where can I sneak a peek at Paul's trimming chart?

John

Alan,

This is a great thread with lots of info to set up a 40 - 46 size ship. One thought about why you might be using less capacity, have you compared the fuse side area of the Vector to the Nobler? This could be were the big savings in drag is coming from. The drag on the wing may not be that significant but if the fuse side area is larger for the Nobler then the Vector (most likely the aft fuse area) then as it is dragged around the circle (especially if it is hanging out or in) it could have a lot more drag. If this is so then we need to think about fuse side area as being more important in are ECL ship designs.

Best,           Dennis T