What to check when buying a Savannah

[888z]

Hello,

 

I got my license some weeks ago and now it is time to look for a plane.

 

In my country, Spain, there are some second hand ICP Savannah for sale. Most of them are 100hp and their prices are around 34000 - 43000 euros.

 

I have already seen 2 of them, VG and S versions. As I am new to this area, I have many questions.

 

- Would you go for S versions (rounded and wider fuselage) if the difference is only 3000 or 4000 euros?

 

- Is 1000 hours too much for buying a plane like this?

 

- What is the difference in consumption from 80hp to 100hp? I am told it is a very big difference in consumption .

 

- Any advice on what to check when buying a Savannah?

 

Thanks a lot!!!

 

[IBob]

Hi 888z and congratulations!
Some things to be aware of for starters:

Some early models of the 912 were vulnerable to crankcase fretting ($$$$$).
Early 912s have a 1500hrs TBO, later models have a 2000hr TBO.
Later 912s have a much improved ignition retard for starting. Poor starting on earlier 912 could lead to sprag clutch damage ($$$).
So, I'd be looking for a 2000hr TBO engine, recent enough to have the new ignition soft start setup.
Also, the 912 has a 5year rubber replacement requirement, including the fuel pump and all the engine hoses. There is some cost in this, so when is it due?
Rotax have an excellent website with a user's forum where you can read up on all this.

Be aware also that the Savannah has comprehensive 1000hr checks to be carried out on the airframe. Again there is some cost, so when is that due?

Apart from that, I would be looking at the general condition of the aircraft, how it has been cared for. And I would be going through the maintenance records to see that it has been kept maintained and if there is any damage history.
I would most strongly recommend that you get an experienced aviator and/or maintanance person to check over the aircraft and paperwork with you.

As for VG vs S model:
Most VGs will have the older engines: (see above)
The S is definitely more roomy and that is an improvement. (It also has more baggage space if  it has the extended baggage mod, though baggage is still limited to 20Kg).
The VG probably has the edge on the S when it comes to STOL, though the S is still very good.
The S is a bit faster in the cruise, though we're not sure why.
Also, these are lightly constructed aircraft and will have a shorter working life than older GA aircraft.
So, generally speaking, I would go for the S unless your main aim is to win STOL comps.

Finally, 80 vs 100hp:
I cannot comment on fuel consumption. But I think you will appreciate the additional performance of the 100hp engine, and especially if you will be doing STOL work and/or will be flying with a passenger (loading makes a big difference).

Happy hunting and let us know how you go!

 

[IBob]

PS: some S models come with long range fuel tanks, 4 instead of 2, and that is the standard arrangement in Australia and NZ.
If you are going to make longer trips this can make a real difference: the 912 runs on mogas, which is not always available and may require multiple trips to town, while away, in order to refuel.

[skippydiesel]

IBob - I commend your very helpful list of "..things to be aware of.." however think the Rotax information, is a tad skewed;

 

Some early models of the 912 were vulnerable to crankcase fretting ($$$$$). Very much depends on engine hours AND how the aircraft has been operated/maintained
Early 912s have a 1500hrs TBO, later models have a 2000hr TBO. Almost meaningless, as most Australian Rotax 9's will run out of Calendar TBO long before they make engine hrs TBO. Added to this is the well documented ability of Rotax 9's to exceed engine TBO , happily chugging away for very many hours past.

Later 912s have a much improved ignition retard for starting. Poor starting on earlier 912 could lead to sprag clutch damage ($$$). Sprag Clutch damage is most likely caused by poor battery replacement strategy ie persisting  with weak/low cranking speed battery puts extra "strain" on the start system. Further the Soft Start system can be easily retrofitted in whole or part.
So, I'd be looking for a 2000hr TBO engine, recent enough to have the new ignition soft start setup. See preceding comments
Also, the 912 has a 5year rubber replacement requirement, including the fuel pump and all the engine hoses. There is some cost in this, so when is it due? While it may be a cost shock to the unaware, that a "rubber replacement " is due - this just part of the routine (like filling the fuel tank)  operating cost of a Rotax 9 and with a bit of research/ingenuity the cost can be minimised, coming in  a long way below the cost of just purchasing the service  items from the Rotax/Aircraft dealership.

 

When it comes to the (any) engine;

• A good/detailed maintenance history is a must.
• Service items should be of good quality ie  meeting/exceeding Rotax standards
• Fuel used - routine use of AvGas has negative  implications
• Compression/Leak Down tests can give valuable insight into engine condition.
• Oil consumption.
• How the prop pitch has been set ie on WOT or Static may give clues as to the likelihood of an engine suffering  "crankcase fretting"
• Frequency of use - low hours are not always good.
• Cooling system performance ie is the engine routinely running cold/hot - almost as bad as each other.
• How the aircraft is used - training - STOLL activity - cruising - club - single/shared ownership - number of owners - routine engine operating rpm (low is as bad as overspeed).
• At around 1200 hrs the gearbox should be inspected and worn parts replaced
• Engine cleanliness/neatness - I have always believed that good engine care, starts with a clean tidy engine. Not talking sparkling, just nice and tidy. Quality aircraft approach eg Hoses/cables appropriately secured. Heat shielding where required (this can be overdone). No open holes in the firewall. No oil/fuel staining. Nothing loose. Etc.

I hope my comments will be viewed as being constructive,

[IBob]

All good comments, Skippy.

 

I have no idea if they have an on condition program for the 912 in Spain, something that 888z may need to look into.

 

My thought with the soft start is that it is well worth having, the difference in starts in huge. The fact is that the older retard system (still present in the new system, but essentially overridden) is very poor and makes for some messy starts even with battery and wiring etc all in good order. And poor starts are hard on this engine.

While the soft start can certainly be retrofitted, most owners do not shell out for 2 new ignition modules to do so.

Edited August 13, 2023 by IBob

[Kyle Communications]

And a new flywheel too Bob...I personally dont believe there is really any difference between softstart and not..its the way you start the engine is the main thing. I have my modules on my engines but havent wired up the softstart as I never get any bacfires 

 

[pluessy]

Fuel burn on the 80hp is around 14lph at 75% (91 octane), the 100hp uses around 18-19lph, but minimum 95 octane (premium). Here in OZ that makes a big difference in fuel price (UL95 is ~$.15 and UL98 ~$0.20 more than UL91). Many European countries have much smaller differences and some don't even produce UL91 any more.

Edited August 13, 2023 by pluessy

[IBob]

35 minutes ago, Kyle Communications said:

 

40 minutes ago, Kyle Communications said:

And a new flywheel too Bob...I personally dont believe there is really any difference between softstart and not..its the way you start the engine is the main thing. I have my modules on my engines but havent wired up the softstart as I never get any bacfires 

 

Mark, the new flywheel shifts the retarded ignition point by 1degree.....is that right?
I would have thought the soft start modules would work fine, regardless of flywheel type???

[Kyle Communications]

it shifts it 2deg but thats what I mean..I dont believe it makes any difference due to the way the modules work. When starting the modules are full retard. They do not change to full advance until around 800 rpm..the engine isnt even running by then it wont even idle until about 1400 rpm. So just putting sofstart modules in with a older flywheel will really do nothing. The original softstart. modules hold the engine in full retard for about 6 sec at idle...really a waste of time and the engine runs like aa hairy goat for 6 sec. if you have a neww flywheel well yes the engine will fire 2 deg earlier but really does that make much of a difference????... maybe it does but not that I can perceive..I have done testing.

By starting the engine in a certain way you will limit any backfiring anyway. You have to remember these are CDI NOT magnetos

 

[Kyle Communications]

I thought it was 2 deg from the original. I am sure I read that somewhere.

This just means the engine fires 2 deg earlier than the original flywheel. Whether that actually makes the ignition point any better to stop backfiring I am not sure but it didnt seem to when I did some testing on 2 engines.

All the softstart does is hold the engine from changing from full retard to full advance by 6 seconds. When the engine changes it is basically just like you turn a switch on and off. One moment it is full retard then immediately it changes to full advance...nothing in between. It doesnt ramp or do anything just a direct switch. I will do a video and show you. I think I may have a old module here I can show you.

The old original modules used to switch over at around 1050 rpm when they had the old switching output devices. When the later version modules came out they changed to a different output device and this shifted the change back to around 800 rpm. I use a different device in my modules which are a higher voltage and higher current rating but they do the change at the 800 rpm as well. I set my modules to hold the engine in retard after start for 2 sec and not 6 sec lie the originals

[IBob]

According to my Heavy Maint Manual, the old flywheel is 4deg before TDC, the new is 3deg before TDC, and they both then shift to fully advanced at 26deg before TDC.
Part of the problem with the original setup is that each ignition module has two trigger coils and each of those trigger circuits is doing it's own thing, trying to measure trigger pulse amplitude to decide when to flip from ignition fully retarded to ignition fully advanced. So unless all four of those trigger coils are gapped and performing exactly identical in output, it's possible to have part of the ignition still firing retarded and part of it advanced.
I'm kinda amazed they went into production with this.
What the so called soft-start does is override all that and force all 4 trigger circuits to the fully retarded state, holding them there until several seconds after the starter is released, by which time the engine is up to reasonable speed, so all 4 trigger circuits then cut promptly to fully advanced.
I can only speak from my own experience, but in 250+hrs I have never had a rough or dirty start. And while the shift from retarded to advanced is quite evident when it happens, my engine does not run rough during the start.

Understanding how the choke mechanism operates is also important in all this.

I am also told, by a very experienced instructor who also runs his own older 912 with a Bolly prop, that the (older system) club Tecnams with their heavier props are a different challenge again when trying to ensure clean starts.

[skippydiesel]

I owned a 2000 delivered Rotax 912 ULS  for 10+ years - never had a staring problem.

Now have a 2019 Rotax 912 ULS still no problem.

Small sample to be sure but it makes me wonder why some people have a problem with starting their Rotax 9's - technique???

[Kyle Communications]

The reason they backfire Bob is is a couple of them. The main one is tecnique and also if the aircraft has a aircraft keytype switch fitted which is used for magnetos NOT CDI. CDI need the 2 separate switches.

The reason they backfire is the prop/engine is turning too slow when spark is applied , heavy props and spacers also make ths problem worse.

This is why separate switches are better. With the switches off you spin the engine with the starter and you will usually hear the spinning RPM go up after a few seconds of spinning this is when you turn 1 switch on then once it fires and ramps up towards idle then just flick the other switch on. This also tests your CDI if you alternate the switch to start each time you start the engine.

When you just click on both switches first or use the aircraft keytype switch which essentially does the same thing then because the CDI will start to send a spark at about 150 RPM the engine is under heavy prop load and only just getting to start level in spark and with extra fuel in there from the choke the engine can easily backfire.

 

When you spin the engine up first without any ignition switch on the engine has a chance to get to 200 or so RPM possibly more with a lighter prop combination and the inertial then helps stop any backfire when you hit the ignition.

Other factors like crappy earths from the battery to the engine block or small DC cables from the battery to the engine dont help the process either. I was shocked when I first got into these aircraft that so many just earth at the battery and let a riveted alu frame pass the negative to the engine block. Not running a earth directly from the battery as well as the one to the frame to the engine block is just wrong.

 

 

 

 

 

 

 

[IBob]

Skippy, I would think principal factors would be technique, prop weight, and size of power wiring/distance to battery. Note also some aircraft do not have a negative battery cable, but rely on hull ground, which can be less than ideal: if the engine does not turn over briskly on the starter, something needs to be done about it.
After that, I would suspect the setup/gap of the trigger coils, especially if one of them was a bit tight, which could lead to a premature spark advance on that part of the circuitry. As described elsewhere, they need to be gapped to spec. using non-ferrous feeler gauges, as ferrous gauges will stick to the magnets and feel just like a good fit even when they are not.  It's a good idea also to check the setting using a go/no go combination of the required gap then the next size up.

[888z]

Hello guys, I wasn't expecting all these answers. Really thanks for the fast ans super well explained support.

 

IBod 

On 13/08/2023 at 1:58 AM, IBob said:

Some early models of the 912 were vulnerable to crankcase fretting ($$$$$).
Early 912s have a 1500hrs TBO, later models have a 2000hr TBO.
Later 912s have a much improved ignition retard for starting. Poor starting on earlier 912 could lead to sprag clutch damage ($$$).
So, I'd be looking for a 2000hr TBO engine, recent enough to have the new ignition soft start setup.
Also, the 912 has a 5year rubber replacement requirement, including the fuel pump and all the engine hoses. There is some cost in this, so when is it due?
Rotax have an excellent website with a user's forum where you can read up on all this.
Be aware also that the Savannah has comprehensive 1000hr checks to be carried out on the airframe. Again there is some cost, so when is that due?

Apart from that, I would be looking at the general condition of the aircraft, how it has been cared for. And I would be going through the maintenance records to see that it has been kept maintained and if there is any damage history.
I would most strongly recommend that you get an experienced aviator and/or maintanance person to check over the aircraft and paperwork with you.

As for VG vs S model:
Most VGs will have the older engines: (see above)
The S is definitely more roomy and that is an improvement. (It also has more baggage space if  it has the extended baggage mod, though baggage is still limited to 20Kg).
The VG probably has the edge on the S when it comes to STOL, though the S is still very good.
The S is a bit faster in the cruise, though we're not sure why.
Also, these are lightly constructed aircraft and will have a shorter working life than older GA aircraft.
So, generally speaking, I would go for the S unless your main aim is to win STOL comps.
 

Thanks for the guidance IBod. It looks the Savannah VG had the 912 ULS fitted on them in Spain, at least the ones on sale at the moment. Thanks for the advice about this, I will always look for 912 engines of 2000 TBO and better ignition.

 

Nice advice about the 5 years for rubber and fuel pump replacement. 1000hr checks to the airframe too.

 

I thought the wider model was only for the Savannah XL version. Like cars, the S version is the best. It has 2000 TBO (like many VGs), it is wider like the XL, Vortex instead slots, and has the rounded fuselage corners which is nicer. If the price difference is only 3000 or 4000 euros in the second hand market, it looks the best option.

 

On 13/08/2023 at 2:04 AM, IBob said:

PS: some S models come with long range fuel tanks, 4 instead of 2, and that is the standard arrangement in Australia and NZ.
If you are going to make longer trips this can make a real difference: the 912 runs on mogas, which is not always available and may require multiple trips to town, while away, in order to refuel.

I didn't know about the 4 fuel tanks option, thanks. Everybody uses Mogas for the ultralights in the aerodrome where I go, so it is ok.

 

On 13/08/2023 at 7:08 AM, skippydiesel said:

• A good/detailed maintenance history is a must.
• Service items should be of good quality ie  meeting/exceeding Rotax standards
• Fuel used - routine use of AvGas has negative  implications
• Compression/Leak Down tests can give valuable insight into engine condition.
• Oil consumption.
• How the prop pitch has been set ie on WOT or Static may give clues as to the likelihood of an engine suffering  "crankcase fretting"
• Frequency of use - low hours are not always good.
• Cooling system performance ie is the engine routinely running cold/hot - almost as bad as each other.
• How the aircraft is used - training - STOLL activity - cruising - club - single/shared ownership - number of owners - routine engine operating rpm (low is as bad as overspeed).
• At around 1200 hrs the gearbox should be inspected and worn parts replaced
• Engine cleanliness/neatness - I have always believed that good engine care, starts with a clean tidy engine. Not talking sparkling, just nice and tidy. Quality aircraft approach eg Hoses/cables appropriately secured. Heat shielding where required (this can be overdone). No open holes in the firewall. No oil/fuel staining. Nothing loose. Etc.

 

 

Hi Skippydiesel. What cons can have to buy an ex-training Savannah (apart from many hours of use), and should I be checking anything particular on these kinds of planes? All the Savannah planes that I see were from "schools" in the past.

On 13/08/2023 at 7:34 AM, IBob said:

I have no idea if they have an on condition program for the 912 in Spain, something that 888z may need to look into.

We have he same 1500 - 2000 hrs TBO for new Rotax engines in Spain.

 

23 hours ago, pluessy said:

Fuel burn on the 80hp is around 14lph at 75% (91 octane), the 100hp uses around 18-19lph, but minimum 95 octane (premium). Here in OZ that makes a big difference in fuel price (UL95 is ~$.15 and UL98 ~$0.20 more than UL91). Many European countries have much smaller differences and some don't even produce UL91 any more.

It seems a lot more consumption. We only have 95 octane and 98 octane in Spain. 25% difference is a lot, but I think we only got Rotax 912 100hp in this country or this is what I was told.

 

Thanks for the other messages about ignition and electric system. The "trick" we do at the school when cutting off the engine (we have an old Bingo with Rotax 503) is to cut the last magneto while pressing the choke mechanism to avoid backfiring.

 

Thanks guys!

[888z]

Hello,

 

I just got some news. Maybe we can get newer Land Africa for a good price.

 

What do you think about the Land Africa compared with the Savannah? Are they exactly the same?

 

This plane have a Rotax 912 with 80hp, which I think it is much better from consumption. As we said about -25% less consumption.

 

Thanks!

Edited August 14, 2023 by 888z

[IBob]

888z here is a link to an excellent site, where the owner has done a great deal of work on the question of slats vs vortex generators. I recommend reading up on this, if you have not already done so:

https://www.stolspeed.com/slats-v-s-vgs

 

 

As for fuel economy: I think I'd be right to say pretty much nobody down this way fits an 80HP engine.
Part of the reason for this is that the fuel consumption is only a part of the ongoing cost of owning and running an aircraft, and the extra $$$ on fuel and consumption is well spent in terms of range and performance. The ULS is also a better proposition when it comes to resale.

Edited August 14, 2023 by IBob

[Kyle Communications]

The VGXL is the same cabin width as the S version. Everything is the same except the flap/aileron connection method and the rear empange. The S supposedly a little stronger with the curved curfaces but the tail feathers are the same. I have built both versions.

Any 912ULS that is older than around 2007/8 will have the later 6x6 CDI modules from about 2010 onwards they then had softstart available but you had the choice whether to enable it or not this was regardless of the flywheel type

I would get the 100hp engine not the 80hp the weight difference is minimal but the performance is a lot different.

Land Africa??? do you mean Savannah Africa?

They do factory built savannahs for South Africa and do a good job possibly cheaper than you can get a local one for except of course for freight and taxes maybe.

 

 

 

[onetrack]

Land Africa is a Portuguese-built (BRM Costruções Aeronáuticas) version of the Zenith CH 701. Chris Heintz considers the Land Africa aircraft an unauthorised copy of the CH 701. The Land Africa has a larger cabin than a Zenith CH 701.

 

https://en.wikipedia.org/wiki/BRM_Land_Africa

[888z]

7 hours ago, IBob said:

888z here is a link to an excellent site, where the owner has done a great deal of work on the question of slats vs vortex generators. I recommend reading up on this, if you have not already done so:

https://www.stolspeed.com/slats-v-s-vgs

 

As for fuel economy: I think I'd be right to say pretty much nobody down this way fits an 80HP engine.
Part of the reason for this is that the fuel consumption is only a part of the ongoing cost of owning and running an aircraft, and the extra $$$ on fuel and consumption is well spent in terms of range and performance. The ULS is also a better proposition when it comes to resale.

Hey, I just saw this website some days ago and it has good information. By the other side, they sale the Vortex generators, hehe.

 

Yes, 100 hp will be always better but it is more expensive and has more consumption. I was thinking about buying second hand and I have updated my budget to buy a "like new one" option, almost new, for some thousands more...

7 hours ago, Kyle Communications said:

The VGXL is the same cabin width as the S version. Everything is the same except the flap/aileron connection method and the rear empange. The S supposedly a little stronger with the curved curfaces but the tail feathers are the same. I have built both versions.

Any 912ULS that is older than around 2007/8 will have the later 6x6 CDI modules from about 2010 onwards they then had softstart available but you had the choice whether to enable it or not this was regardless of the flywheel type

I would get the 100hp engine not the 80hp the weight difference is minimal but the performance is a lot different.

Land Africa??? do you mean Savannah Africa?

They do factory built savannahs for South Africa and do a good job possibly cheaper than you can get a local one for except of course for freight and taxes maybe.

The VG is not the same in Spain, it has not rounded corners (the one I personaly saw and the ones in internet). Correct me if not!

 

Land Africa (BRM) is a Portuguese version of the Savannah, like onetrack says. 😅

[IBob]

6 hours ago, 888z said:

Hey, I just saw this website some days ago and it has good information. By the other side, they sale the Vortex generators, hehe.

 

Yes, 100 hp will be always better but it is more expensive and has more consumption. I was thinking about buying second hand and I have updated my budget to buy a "like new one" option, almost new, for some thousands more...

The VG is not the same in Spain, it has not rounded corners (the one I personaly saw and the ones in internet). Correct me if not!

 

Land Africa (BRM) is a Portuguese version of the Savannah, like onetrack says. 😅

888z nobody here is trying to sell you anything. You asked for information to help you choose, people are responding by pointing you to information that may be useful. Part of that is understanding why there was a general move away from LE slats to vortex generators. And the Stolspeed owner was foremost in that and there are very good studies on his website.

With the engine size and fuel consumption there is no magic : x fuel in gives you y hp/kw out. The 80hp engine will give you an aircraft that requires a longer takeoff run, climbs slower, and cruises slower. It's that simple.

Regarding the Savannahs, there is some confusion with the naming, which seems to vary a bit from country to country.
1. Here in NZ I do not think we have any of the original models with the LE slats.
2. We have the next model, which is called the VG because they removed the slats and added the vortex generators
From there, ICP remodelled the fuselage in 2 stages:
3. We have the model after the VG which is called the XL or VGXL. This has the remodelled front end, larger cockpit etc, but still has the flat sided rear fuselage.
4. And we have the model after that which is called the S. This has the rear fuselage remodelled and rounded.

 

Finally, so far as i know, nobody imports the BRM aircraft here.


 

[888z]

9 hours ago, IBob said:

888z nobody here is trying to sell you anything. You asked for information to help you choose, people are responding by pointing you to information that may be useful. Part of that is understanding why there was a general move away from LE slats to vortex generators. And the Stolspeed owner was foremost in that and there are very good studies on his website.

With the engine size and fuel consumption there is no magic : x fuel in gives you y hp/kw out. The 80hp engine will give you an aircraft that requires a longer takeoff run, climbs slower, and cruises slower. It's that simple.

Regarding the Savannahs, there is some confusion with the naming, which seems to vary a bit from country to country.
1. Here in NZ I do not think we have any of the original models with the LE slats.
2. We have the next model, which is called the VG because they removed the slats and added the vortex generators
From there, ICP remodelled the fuselage in 2 stages:
3. We have the model after the VG which is called the XL or VGXL. This has the remodelled front end, larger cockpit etc, but still has the flat sided rear fuselage.
4. And we have the model after that which is called the S. This has the rear fuselage remodelled and rounded.

 

Finally, so far as i know, nobody imports the BRM aircraft here.


 

Hello IBob.

 

Here in Spain we only have VG and XL. (Not the VGXL, hehe).

 

I am sorry, I didn't explain well about the website. I think the website you said is great, it has many detailed studies and very usefull information. I spent some hours reading there before you spoke about the website, and after. I just wanted to mean that they sell vortex generators, so it could be normal that they could be a bit subjective or more positive sometimes, it was just a comment that I shouldn't say it because it is a personal opinion. What it is clear is that Vortex generators are the improvement of the slats in the Savannah and they give you better cruise, etc.

 

By the way, thanks to everybody about the information that you are telling me. I didn't expect all these fast and detailed answers and all the information that I get from you all. Thanks a lot to you people from NZ, Australia, etc!!