S8D for noobs?

[James Duffy]

So, under unwavering conditions contestants have to do some pretty fancy flying to stay within the 30 degree cone and under the 400 foot limit?

It essentially can't be done. Any future S8D or S8P activities here in the US, even simple practice flying, will require a waiver to the altitude limitations of paragraph 6 of Section 44809.

That is not an insurmountable hurdle, though, and will be much easier once NAR is accepted as a Community Based Organization (CBO) by the FAA. That process has already been initiated.

 

[kjohnson]

@Doug Holverson S8 is flown a couple of ways. The vanilla S8x event is flown in 3 rounds with a max time each round based on the motor class.
There is a chart in the FAI Spacemodeling rules that shows the minimum wingspan, maximum launch mass, and max time per impulse class.

CLASS	TOTAL IMPULSE Newton-seconds	MAX WEIGHT g	MIN WING SPAN mm	MAX FLIGHT TIME sec
S8A	0.00-2.50	60​	500​	180​
S8B	2.51-5.00	90​	650​	240​
S8C	5.01-10.00	120​	800​	300​
S8D	10.01-20.00	300​	950​	360​
S8E & S8P	20.01-40.00	300​	1100​	360​
S8F	40.01-80.00	500​	1250​	360​

So for S8D you build (or convert) a model with a minimum span of 950mm that weighs less than 300g (ready to fly), and you fly it 3 times trying to achieve a max time of 6 minutes. You can earn 60 bonus points if you land any part of the model within a 15m square box on the ground. The time in seconds is converted into points, and your landing bonus is added so the maximum score in a round could be 420. You fly 3 times, add up all the scores, and if there are any ties there is a flyoff round.

The P version of S8 has been flown at the E impulse level (and size/mass limits) and adds a precision task. During a 12 minute working time window, you need to launch, fly a 6 minute flight, and land at a designated landing spot. Each second you are timed is a point. If you go over 360sec you start losing points for each second. If you land on your spot, you get 100 extra points. For every 10cm away from the spot the nose of your model lands, your landing bonus goes down by 1 point. All the scores are normalized so the highest score gets a 1000, and the rest are assigned relative to that score.

S8EP pilots at the WSMC flew in 4 rounds, the top 5 pilots at the end of those rounds were advanced into 2 final rounds where they flew head to head. The combined scores from those 2 rounds determined the top 5 places.

There was a rules change for the S8P version that keeps the size and mass limits of the E class event, but lowers the impulse to a D (20 Newton-seconds max). Planes that were good at E impulse (1.5m DLG converts) will not be as good in the event going forward.

If you are looking to get into the event, converting a small, cheap 1m DLG is a good way to go, you will need to add some span for the P event. There are some inexpensive ones out there (See the Big Vick from Hyperflight in the UK https://www.hyperflight.co.uk/products.asp?code=BIG-VICK&name=big-vick-1m-dlg for $55, but you can also go out an buy very expensive molded planes too ($400-$700). Either way, you will need to add a motor mount (18mm for D reloads from Aerotech) but the beauty of converting a DLG is you can always fly it as a DLG for practice.

kj

 

[astronwolf]

So, under unwavering conditions contestants have to do some pretty fancy flying to stay within the 30 degree cone and under the 400 foot limit?

I think they had a waiver to exceed the 400-foot limit.

 

[dhbarr]

@Doug Holverson S8 is flown a couple of ways. The vanilla S8x event is flown in 3 rounds with a max time each round based on the motor class.
There is a chart in the FAI Spacemodeling rules that shows the minimum wingspan, maximum launch mass, and max time per impulse class.

CLASS	TOTAL IMPULSE Newton-seconds	MAX WEIGHT g	MIN WING SPAN mm	MAX FLIGHT TIME sec
S8A	0.00-2.50	60​	500​	180​
S8B	2.51-5.00	90​	650​	240​
S8C	5.01-10.00	120​	800​	300​
S8D	10.01-20.00	300​	950​	360​
S8E & S8P	20.01-40.00	300​	1100​	360​
S8F	40.01-80.00	500​	1250​	360​

So for S8D you build (or convert) a model with a minimum span of 950mm that weighs less than 300g (ready to fly), and you fly it 3 times trying to achieve a max time of 6 minutes. You can earn 60 bonus points if you land any part of the model within a 15m square box on the ground. The time in seconds is converted into points, and your landing bonus is added so the maximum score in a round could be 420. You fly 3 times, add up all the scores, and if there are any ties there is a flyoff round.

The P version of S8 has been flown at the E impulse level (and size/mass limits) and adds a precision task. During a 12 minute working time window, you need to launch, fly a 6 minute flight, and land at a designated landing spot. Each second you are timed is a point. If you go over 360sec you start losing points for each second. If you land on your spot, you get 100 extra points. For every 10cm away from the spot the nose of your model lands, your landing bonus goes down by 1 point. All the scores are normalized so the highest score gets a 1000, and the rest are assigned relative to that score.

S8EP pilots at the WSMC flew in 4 rounds, the top 5 pilots at the end of those rounds were advanced into 2 final rounds where they flew head to head. The combined scores from those 2 rounds determined the top 5 places.

There was a rules change for the S8P version that keeps the size and mass limits of the E class event, but lowers the impulse to a D (20 Newton-seconds max). Planes that were good at E impulse (1.5m DLG converts) will not be as good in the event going forward.

If you are looking to get into the event, converting a small, cheap 1m DLG is a good way to go, you will need to add some span for the P event. There are some inexpensive ones out there (See the Big Vick from Hyperflight in the UK https://www.hyperflight.co.uk/products.asp?code=BIG-VICK&name=big-vick-1m-dlg for $55, but you can also go out an buy very expensive molded planes too ($400-$700). Either way, you will need to add a motor mount (18mm for D reloads from Aerotech) but the beauty of converting a DLG is you can always fly it as a DLG for practice.

kj

Would UMX Radian be a reasonable place to start, and would RealFlight Evolution practice be useful?

I'm neither a radio guy nor a glider guy, I just figured using the same controller and plane in the virtual and physical worlds might be better than immediately crashing airframes.

 

[TheAviator]

Would UMX Radian be a reasonable place to start, and would RealFlight Evolution practice be useful?

I'm neither a radio guy nor a glider guy, I just figured using the same controller and plane in the virtual and physical worlds might be better than immediately crashing airframes.

Yes, the UMX radian would be a great place to start. It is relatively durable and you can work lift with it on calm days, though more than a couple of MPH of wind would make it tough for a newbie. More importantly, it can be flown in your backyard in the evenings as the sun is setting and the wind is dropping. There is no replacement for stick time.

 

[James Duffy]

Would UMX Radian be a reasonable place to start, and would RealFlight Evolution practice be useful?

Yes to both, but don't fly the UMX Radian in high winds. Also, I can highly recommend a simple RC car to assist in getting the left-right changes in perspective locked down. Did wonders for me, and it is a great deal of fun!

 

[Cosmoe]

Does anyone out there have any experience with converting a UMX Radian to either a rocket glider or boost glider?

 

[burkefj]

Does anyone out there have any experience with converting a UMX Radian to either a rocket glider or boost glider?

I think that will be too light/flimsy for even small 1/4 1/2 A motors

 

[TheAviator]

Does anyone out there have any experience with converting a UMX Radian to either a rocket glider or boost glider?

Would agree. If you're looking for something in that size, the J&H Carbonette 19 is a good place to start.

https://jhaerospace.com/product/carbonette-19-micro-r-c-dlg-boost-glider/

 

[MJ D]

You post still incorrectly states that S8 type models are not launched vertically.

I launch mine at 75-80 degrees elevation. A typical launch with top motor pod involves some back stick off the pad that is quickly neutralized. Some contestants clearly pitched almost horizontal and were not DQ-ed, others had OK boosts and got called.. the LCO had about the worst possible visual point of reference to judge elevation angles.

So, under unwavering conditions contestants have to do some pretty fancy flying to stay within the 30 degree cone and under the 400 foot limit?

Like not fly the event, yes. S8D will not even stay under this limit.

 

[MJ D]

Does anyone out there have any experience with converting a UMX Radian to either a rocket glider or boost glider?

Not possible, the wings are too flimsy and flexible.

 

[dhbarr]

Is there a recommendation for a gust-friendly & crash-friendly unit that can be converted?

Nobody in my immediate circle flies these, so we're going to need to do a lot of trial-and-error.

 

[mikec]

Is there a recommendation for a gust-friendly & crash-friendly unit that can be converted?

For S8D/E or just in general?

The video linked early in this thread is an excellent introduction for S8 conversions, and he mentions a couple of commercial kits, some of which are not currently available unfortunately.

If you just want to fly rocket gliders and get your feet wet, Dynasoar has some nice kits that don't require as much piloting skill/tweaking.

 

[TheAviator]

Is there a recommendation for a gust-friendly & crash-friendly unit that can be converted?

Nobody in my immediate circle flies these, so we're going to need to do a lot of trial-and-error.

Honestly, if you're still at the crash a lot stage of flying, you'd probably be better served by an electric launch glider. You can't beat the UMX or 2m E-Flite Radian for this purpose.

UMX Radian: https://www.horizonhobby.com/product/umx-radian-bnf-basic-with-as3x-and-safe-select/EFLU2950.html
2m Radian: https://www.horizonhobby.com/product/night-radian-2.0m-bnf-basic/EFL36500.html

 

[TheAviator]

Alternatively, several of the Art Hobby gliders would work well. This would make a good first D-powered model.

https://www.arthobby.com/index.php?page=item&category=29&sub_category=31&item=255

 

[MJ D]

Piloting an RC electric glider proficiently is a good and logical prerequisite for flying any RCRG stuff. Especially considering what you can get out of a box made from EPO foam these days. The E-Flite Night Radian 2m is one example, great flier with remotely switchable gyro stablization. I'm not a big fan of the UMX stuff but the little Radian does fly quite well. And the entire flight is typically under 400' should you be concerned with that factor, whereas the big Radian has just got itself settled into a thermal at that height..

Another question is budget... what are you willing to shell out?

There are a host of 1m DLG models out there, varying availability depending on country of original manufacture*, this is a typical example: 1m DLG example

With a shift to S8D for seniors, I believe the question of 950mm or 1.1m minimum wingspan is still open. The talk was it may be 1.1m so I have held off buying anything for S8D yet until I know what's going on.

* Ukranian models are spotty these days as you can imagine, many popular DLG's come from there.

 

[burkefj]

Alternatively, several of the Art Hobby gliders would work well. This would make a good first D-powered model.

https://www.arthobby.com/index.php?page=item&category=29&sub_category=31&item=255

That one looks pretty reasonable in $$, given that tail shape would it be better suited to put a motor pod on the bottom instead of on the top and just deal with a little pitch up instead?

 

[TheAviator]

That one looks pretty reasonable in $$, given that tail shape would it be better suited to put a motor pod on the bottom instead of on the top and just deal with a little pitch up instead?

Nope, just let the exhaust hit the tail. I've been doing that for years now. You could do the Colibri-V if you're really worried about it, but I have seen no problems as long as there's decent separation between the motor and the tail.

 

[MJ D]

Ditto - with the low thrust long burn motors there is no exhaust damage to the tail. Don't worry about it. Just worry about using an umbilical ignition lead that swings out of the way at ignition - i.e. suspend the igniter leads off at 90 degrees to the motor.

 

[burkefj]

Is there a disadvantage to having the motor tube on the bottom other than landing on it?

 

[kjohnson]

IMO it makes getting the thrust line right a little more difficult, and makes things harder to control. Motor underneath can create a boost that comes back at you that requires down elevator to correct. Having the motor on top rotates the model away from you so some up elevator corrects that. That being said, many countries used bottom mounts successfully for years, as did the Phoenix RCRG kit... you just have to build it in to the model correctly. Top mount allows you to retrofit a motor pod to almost any HLG model.

 

[kjohnson]

Alternatively, several of the Art Hobby gliders would work well. This would make a good first D-powered model.

https://www.arthobby.com/index.php?page=item&category=29&sub_category=31&item=255

My 2nd RCRG project was an Art Hobby Colibri. Good quality for the money, if a little heavy.

My 1st was a Charles River RC Club Terminator HLG with a pylon and motor mount glued to the nose.
http://www.charlesriverrc.org/articles/terminatorhlg/terminatorhlg.htm

 

[MJ D]

Is there a disadvantage to having the motor tube on the bottom other than landing o

IMO it makes getting the thrust line right a little more difficult, and makes things harder to control. Motor underneath can create a boost that comes back at you that requires down elevator to correct. Having the motor on top rotates the model away from you so some up elevator corrects that. That being said, many countries used bottom mounts successfully for years, as did the Phoenix RCRG kit... you just have to build it in to the model correctly. Top mount allows you to retrofit a motor pod to almost any HLG model.

It can work but I see no advantage. I've seen a motor-under S8 loop into the ground on the maiden flight. A bottom mounted pod could be a hassle if you are flying precision landing depending on your approach technique. Plus it snags the ground. The top mounted pod provides a but of helpful downthrust once you've held the nose up for a split second off the pad, whereas bottom mount is always trying to pitch up a glider that already wants to do that to some degree due to normal trim.

The Phoenix was more centerline thrust than low thrust, with the mass of the wing below the motor mount and the motor aimed at the CG.

 

[MJ D]

Another relatively affordable molded 1m DLG.. Mini Dart

More affordable in glass layup versus carbon of course. You don't need to go to the nth degree right out of the gate in your RCRG career, it's 140g versus 125g, and will still fly like a bird. But for competition that is over 10% so would be a strong consideration.

 

[MJ D]

My 2nd RCRG project was an Art Hobby Colibri. Good quality for the money, if a little heavy.

My 1st was a Charles River RC Club Terminator HLG with a pylon and motor mount glued to the nose.
http://www.charlesriverrc.org/articles/terminatorhlg/terminatorhlg.htm

Many fliers got into S8E using the Art Hobby Zuni-DL or Zuni-V (standard or v-tail versions). I am actually just assembling a Zuni-DL for my son to sport fly, I never did build an S8 out of it. I flew a Stilletto this year, but it's too big for serious S8D. It boosts to the moon on E's though, really tests the eyesight and orientation.

 

[dhbarr]

Honestly, if you're still at the crash a lot stage of flying, you'd probably be better served by an electric launch glider. You can't beat the UMX or 2m E-Flite Radian for this purpose.

UMX Radian: https://www.horizonhobby.com/product/umx-radian-bnf-basic-with-as3x-and-safe-select/EFLU2950.html
2m Radian: https://www.horizonhobby.com/product/night-radian-2.0m-bnf-basic/EFL36500.html

My basic plan then, is to start him out on Real Flight simulator but with a real controller. I confirmed the UMC Radian is modelled in their sofware.

Is the NX8 a good move here? Too much, not enough?

 

[burkefj]

My basic plan then, is to start him out on Real Flight simulator but with a real controller. I confirmed the UMC Radian is modelled in their sofware.

Is the NX8 a good move here? Too much, not enough?

It's probably more than you need but it's kind of a one time investment and you can grow into it if you can afford it.

 

[David_Stack]

My basic plan then, is to start him out on Real Flight simulator but with a real controller. I confirmed the UMC Radian is modelled in their sofware.

Is the NX8 a good move here? Too much, not enough?

You may want to 'shop around' in the RC Groups classifieds as well (assuming you are not averse to buying pre-owned). NX8's seem to be selling in the $225 - $250 range...

 

[aerostadt]

I have been using the umx radian and the Real Flight simulator. It is good practice. I think the small electric is good experience, but not quite like a Dynasoar rocket glider. You have a throttle and tail elevator and rudder controll. I got the old OOP Cox Cruiser to work somewhat.

 

[aerostadt]

The radian is very light and is very good for noobs like me for developing strategies for flying light rocket gliders. One thing I have done is take the radian up high on the simulator and then kill the throttle, and then practice landing as glider.