How many using the SK-GPS Positioning Module

[brw0513]

I'm doing some research now trying to decide if an SK-720 Black Edition paired with an SK-GPS Positioning Module is a good choice for me.

The price of both takes the breath away but if this combination works as advertised then this may be just what I need to progress in the hobby.

There doesn't seem to be much chat here about the SK-GPS module.

How many users are there?

Is it a gimmick or worthwhile choice in the right application?

Keen to hear of personal experiences.

[Xrayted]

I have one, and it has always worked as advertised for me. It will all depend on specifically what your intentions are for using it. Using GPS on 3D helis is a new and evolving technology, so nothing is foolproof at the moment, but let us know your intentions and goals, and we can give you some better and more specific info to help.

[mhoebrec]

Originally Posted by Xrayted

I have one, and it has always worked as advertised for me. It will all depend on specifically what your intentions are for using it. Using GPS on 3D helis is a new and evolving technology, so nothing is foolproof at the moment, but let us know your intentions and goals, and we can give you some better and more specific info to help.

+1

[bavci_0655]

I bought this combo for this purpose. But I can't thrust its rescue function. Almost every flight it lost gps connection with satellites. And if there aren't enough connection it will not rescue your helicopter. So if you want better rescue, look for BD3SX or Spirit. They don't use gps for rescue.

But I can say it's a good flybarless unit. For me, only thing that needs to be improved is governor (compared to Vbar).

[SpeedTape]

Originally Posted by bavci_0655

So if you want better rescue, look for BD3SX or Spirit. They don't use gps for rescue.

You don't need GPS for basic rescue on the SK-720 either. Adding a GPS gives the gyro more information to work with and allows things like return to home and position hold, but the SK-720's self leveling already works quite well without it.

[Inkslinginmofo77]

If u would like to advance your skills as a pilot it is a terrific safety net. Realistically u don't need it for a rescue now function as self level can be configured to do so. But self level won't lock position so it can drift on way or the other. This gps is one of the most feature rich GPS's on the market and is by no means gimmicky. It provide a large satety net with many gps functions such as position hold, hard deck, soft deck, altitude lock, lock grid, lock radial, return to home, etc. read the manual for the gps here.

http://www.skookumrobotics.com/downl...Manual_110.pdf

Towards the end it gives a list and description and illustration of the gps features and functions. And I own the SK-720BE/GPS combo as well as a naza. And I will tell u straight up, naza blows compared to skookum. Skookum has far superior locked in control and smoother attitudes. And more crisp control. The interface is has more options to configure to fine tune to your liking. So If u wanna protect your investment then this will not let u down

[Luvmyhelis]

I ran the Gps for about a season and a half before taking my gps off the heli. Why? I simply didn't use it much enough to justify having it on there. But it did perform exactly as advertised. I went out several times with large groups watching and simply set my tx down on the ground and watched my Gob 700 hovering hands free while frozen in one spot. Just to show the guys how incredible that feature was. RTH is also amazing. My 3d flight skills are at the point where I haven't felt I needed the gps or rescue functions at all for the last few years. But there has been a time or two where the bailout function alone literally saved my helis. I figure the cost of just one save alone worth the entire investment. And the Skookum data logging, aka vibe analysis tool is just superb and worth every penny all by itself.

It did take me quite a while to sort out my gov feature, but I am running some pretty gnarly custom wound 14s motors in my helis and they just had a rough time seeing loads until I started flying hard enough for them to respond correctly. Almost all the other guys I fly with have Skookum equipped helis that run on the gov perfectly. As did my own when running normal factory motors.

Help here in this section is simply amazing!

[brw0513]

Originally Posted by Xrayted

......but let us know your intentions and goals, and we can give you some better and more specific info to help.

This may sound strange but most of the enjoyment I get out of the hobby is not really by flying My real passion is spark ignition engines. At the moment I'm busy making some sideframes to accept a spark ignition engine.

What I really want to do is get to the flying field and put my latest design through a "scale like" test without fear of crashing to ruin the day/week/month. No doubt I'll need many airframe iterations to get to the point that I'm happy with the outcome (i.e. cooling options to keep engine temp under control, CoG position etc). What I don't want to happen is to let my lack of flying skill rule over my progress in airframe design.

I'd also prefer to spend money on a new engine rather than airframe parts

It's not that I can't fly but I'm not all that good. I have an MCPX that I can hoot around with and can hover nose in for 4 mins. But when I try new things it doesn't take too long for things to go pair shaped.

The good lord could take me if ever I could do a passable F3C routine.

Do I sound like a candidate SK-GPS user?

Was there ever a hardware update to the SK-GPS module? There is a module on the second hand market here at the moment but not sure if it is a current or superseded version.

Thanks all.

[Xrayted]

Originally Posted by brw0513

This may sound strange but most of the enjoyment I get out of the hobby is not really by flying My real passion is spark ignition engines. At the moment I'm busy making some sideframes to accept a spark ignition engine.

What I really want to do is get to the flying field and put my latest design through a "scale like" test without fear of crashing to ruin the day/week/month. No doubt I'll need many airframe iterations to get to the point that I'm happy with the outcome (i.e. cooling options to keep engine temp under control, CoG position etc). What I don't want to happen is to let my lack of flying skill rule over my progress in airframe design.

I'd also prefer to spend money on a new engine rather than airframe parts

It's not that I can't fly but I'm not all that good. I have an MCPX that I can hoot around with and can hover nose in for 4 mins. But when I try new things it doesn't take too long for things to go pair shaped.

The good lord could take me if ever I could do a passable F3C routine.

Do I sound like a candidate SK-GPS user?

Was there ever a hardware update to the SK-GPS module? There is a module on the second hand market here at the moment but not sure if it is a current or superseded version.

Thanks all.

The potential issue I see with your plan is the engine itself and the vibrations it will cause.

The GPS module must be paired up with the 720 FBL unit because the 720 has accelerometers within in for its self leveling. The GPS taps into that self leveling data and uses it combined with its GPS and altimeter info for the total functionality.

Vibrations can confuse accelerometers to the point of not knowing what level is anymore, so the 720 is designed to shut these features down if the vibes exceeded a certain level to avoid a dangerous situation, and the heli doing something unpredictable.

This is rarely an issue on our smooth electrics, and there are some that have even had success with nitro motors with enough isolation of the FBL unit, but I'm not so sure a gas engine would be such a great candidate. Let's see what others think, but I would hate to see you spend $1000 only to find that the unit is unlikely to operate in the environment that you need it for.

To answer your last question, the GPS hardware is still the same, but is in its third firmware revision at the time, which is easily updated online.

[Luvmyhelis]

Great advice as usual! Most spark ignition motors out in the market, if not all have a tendency to vibrate rather wickedly. It is pretty tough to get the Skookum isolated from the severity of the vibes without it being rather mushy at the sticks. About the only way I can see this being done effectively is by using a concept using a suspension platform mount for the fbl unit. Only two guys I know of have done any testing at all with this.

[Xrayted]

I've been thinking about this, and the OP states that the intended purpose would be for flight testing the gasser in custom frames without fear of crashing so easily since he doesn't have a lot of flight experience.

If this is the case, and the OP at least has the skills to hover, then I would think that something like self leveling alone would be all that is needed, and make the heli as stable as a coaxial trainer.

Once again we are back in the same situation with the SL in the SK FBL unit due to vibes, but there are those that claim the Bavarian Demon 3SX self leveling is immune to vibes due it's different technology that doesn't use the accelerometers that are bothered by the vibes.

Now I don't know for sure if it's up to a gasser since I've never used the BD, and I know it may be considered sacrilegious to suggest considering another product in this forum, but for me it's about getting what's right for the job to help a fellow modeler and not brand loyalty just for the sake of it

Maybe it's worth checking in the BD forum and see if anyone there is running their FBL controllers on gassers and how well the SL rescue on their units are working. It would cost half as much if it works since the BD is $500.

Another option would be the new Spirit FBL controller which is essentially using the same licensed SL technology as the BD but at half the price at $250. The problem with the Spirit at this point is finding one in stock since they tend to sell out immediately as a new player in the SL FBL market due to the low cost compared to others.

[Luvmyhelis]

Originally Posted by Xrayted

I've been thinking about this, and the OP states that the intended purpose would be for flight testing the gasser in custom frames without fear of crashing so easily since he doesn't have a lot of flight experience.

If this is the case, and the OP at least has the skills to hover, then I would think that something like self leveling alone would be all that is needed, and make the heli as stable as a coaxial trainer.

Once again we are back in the same situation with the SL in the SK FBL unit due to vibes, but there are those that claim the Bavarian Demon 3SX self leveling is immune to vibes due it's different technology that doesn't use the accelerometers that are bothered by the vibes.

Now I don't know for sure if it's up to a gasser since I've never used the BD, and I know it may be considered sacrilegious to suggest considering another product in this forum, but for me it's about getting what's right for the job to help a fellow modeler and not brand loyalty just for the sake of it

Maybe it's worth checking in the BD forum and see if anyone there is running their FBL controllers on gassers and how well the SL rescue on their units are working. It would cost half as much as well if it works. Another option would be the new Spirit FBL controller which is essentially using the same technology as the BD but at half the price. The problem with the Spirit at this point is finding one in stock since they tend to sell out immediately as a new player in the SL FBL market due to the low cost compared to others.

Funny you posted this as I was fighting the same thought train before answering. However I know of half a dozen guys that have had the BD turn their heli over during high vibe episodes. So the claims it is immune, are not based on this level of vibes. Quite a few guys have tried the BD on their gasser/nitros and had the same experience also. The very economical Ikon also has a pretty good working SL, but again it is seriously vibe prone. So to date I am not sure that there are any valid bullet proof options here without some work involved?

[Xrayted]

Good to know

[brw0513]

Thanks for the replies. They are appreciated. It certainly requires more consideration before sinking $1000 into a half-considered purchase.

The engine I'm using is an OS GT15HZ. In my mind, if it's tuned well enough, it shouldn't be any more vibey than a similar displacement nitro variant. I find it hard to believe fuel type alone is a significant source of vibes.

My airframe design steals pretty heavily from a Blitz Avro. It has a primary belt drive and the gyro platform is isolated by rubber grommets.

It would be good if Skookum offered some sort of software filtering wizard to eliminate the specific frequency contribution from a nitro/gas engine. If the goal of a governor is to maintain a constant engine speed within a given limit then it's "imbalance" bandwidth could be quite narrow.

[sctholson]

In late October I picked up a Goblin 700 and a Leviathan conversion kit and was determined to use the 720 on it. No reason to use the GPS. My early tests showed that the soft foam, metal plate, thin foam mount worked pretty well. Overall vib scores in hover and light flight were around 2. Not bad and acceptable.
However then the cold weather kicked in and that soft foam became rigid foam and with that change the vibrations just transferred through the foam to the 720. Overall vibe scores jumped to 10 and higher consistently. Wanting to fly in the winter I ended up putting on the Bavarian Demon BD3sx. The BD is known to me more vibe tolerant, but not totally immune.
My engine has a huge up down (32 on the graph) spike which I traced back to significant end play in the crankshaft.
Even with the high vibs the 720 flew fine, but I knew the SL wasn't going to work. The BD hasn't demonstrated any problems at this vibration level and the Rescue function works as advertised. The BD has no governor so that's a bummer.
I could have tried to reduce the end play in the crank, but ultimately I thought even if I fixed the engine, I was still flying on the "vibration" edge of what the 720 was able to tolerate. I needed to have the assurance that during 3d moves the vibration wouldn't trip the vibe scale and ultimately I didn't think I could count on it.
I miss the vibe analysis and governor though. As a substitute I have run a piggy back 720 on the heli at times to obtain a vibration graph. It's harder to read when the scale is up to 30+ though. The engine is a dominant force on that graph.

[Luvmyhelis]

Excellent post and info!

[remoterecon]

I'm using the SK720BE and the GPS and absolutely love it.

It's mounted on a LOGO 550 SE, so very low vibs and quite nimble helicopter.

[Mostly]

Works for me as I never have time to react when things go out of control.
I try not to activate it, but it is there.
Effectively this give two lines of defence, me first followed by the Harddeck

Best to carry out testing reasonable high to get confidence.

Now I just check I have the green lights after flight and blue on the satellite

M